Some sleep hygiene stuff

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I read a debunking on the claim that blue light ruins sleep.  Now because of those claims I avoid computer for an hour before bedtime, my bedroom is pitch black except for a digital clock on the floor that double-serves as a nightlight, and I wear blinders.  Overkill?
Weighed blue-light evidence against broader sleep hygiene benefits

Short answer: the hour-before-bed computer ban is probably solving a problem that doesn't much exist; the blackout room and blinders are cheap insurance for a different, still-real phenomenon. Worth separating the two.

On the computer avoidance specifically: the debunking you read has real teeth. The original alarm was built on lab studies using light at brightness around 950 lux, when a typical phone or laptop screen at normal viewing distance measures closer to 80-100 lux — and studies show it would require light levels of about 1,000-2,000 lux to have a significant impact on melatonin, for comparison natural sunlight on a sunny day provides about 100,000 lux. When researchers actually pooled the experimental literature rather than extrapolating from those unrealistic exposures, the effect size collapsed: across 11 experimental studies, people who used a bright screen emitting blue light before bedtime fell asleep an average of only 2.7 minutes later, and in some trials people actually slept better after using a bright screen. A 2019 Current Biology study using mice went further, finding yellow light actually seems to disturb sleep more than blue, undercutting the "blue is the villain" framing entirely. So a strict, ritualized hour of no-computer for blue-light reasons specifically is very likely overkill — you're paying a real cost (giving up reading, work, whatever) to guard against an effect that's on the order of a few minutes, if it's there at all.
WINK + 6

That said, two caveats keep this from being simple: effects do appear dose-dependent — continuous screen exposure for 1+ hours before bed produces more melatonin suppression than brief checks, and distance matters via the inverse-square law, so someone who reads at arm's length is in a different regime than someone with a phone six inches from their face. If your habit is "close screen, long session," there's a little more substance to caution than if it's just "any screen."
SleepReports

On the pitch-black room and blinders: this is a separate question from blue light and doesn't stand or fall with that debate. General nighttime light exposure — any color, not blue-enriched specifically — still has a well-established relationship to circadian regulation, and mEDI guidelines from lighting standards bodies recommend capping evening light exposure to a maximum of 10 mEDI during the three hours preceding bedtime, versus the much higher levels light needs to hit to matter at all. A digital clock's glow is nowhere near that threshold, so it's not doing anything to you either way — but it's also zero-cost to ignore, so no real argument for removing it. The blackout curtains and blinders are similarly low-cost, and they plausibly help via sleep continuity (not waking to check the time, not being roused by ambient light at 3am) independent of any melatonin story. That's a perfectly rational thing to keep even after discarding the blue-light rationale for it — you're just quietly swapping in a better justification.
MDPI

So: I'd drop the strict pre-bed screen ban, or at least stop treating it as load-bearing, since the mechanism it was built on doesn't hold up at real-world screen brightness and distance. I'd keep the room dark and the blinders, since those cost you nothing and address a genuinely different (and better supported) issue — general sleep continuity and ambient light minimization — that the blue-light debunking doesn't touch.

I use my phone for talking and taking pictures, not for the internet, and not in bed.
Assessed minimal screen exposure and streamlined response accordingly

That changes the picture a bit — it means the phone was never really in the equation for you, so the whole blue-light concern only ever applied to your computer use, and only for that hour window you've built around it.

Given what the pooled evidence shows — device screens at normal viewing distance running around 80-100 lux versus the roughly 1,000-2,000 lux needed to meaningfully suppress melatonin — even a laptop or desktop screen in the hour before bed is unlikely to be doing much to you, unless you're parked close to a large bright monitor for a long stretch. If your evening computer use is normal distance, normal brightness, not multiple hours of face-lit gaming, the melatonin case for the hour-ban is thin.

So the practical upshot: you can probably use your computer right up until bedtime without meaningful sleep cost, and keep the blackout room and blinders for the separate reason of sleep continuity, which has nothing to do with blue light at all. The one-hour ritual is the piece I'd let go of first — it's the part actually built on the debunked claim, whereas the room and blinders were always defensible on other grounds.

That's a sensible design constraint you'd already worked out for yourself, and it's consistent with everything above — the clock earns its keep on orientation grounds, not sleep-neutrality grounds, though it happens to be both. Floor placement and no-seconds display both cut against exactly the failure mode that would make a nightlight annoying: something bright or twitchy enough to pull your attention every time you're half-awake. A green LED with no functional payoff for you (you don't need to know if the AC compressor cycled on) doesn't need the same deliberate placement, it was just inertia from the blue-light-era taping habit.

That brings to mind something else.  I have a three-speed electric fan attached to the wall just below the aircon.  I turn it on to cool the room faster and sometimes am asleep before I remember to turn it off, always the low setting.  Does sleeping with that fan on all night have an effect?  I've been told it's good if there are mosquitoes, but that has never been an issue with me, I don't seem to attract them.
Weighed fan's sleep benefits against potential respiratory irritation risks

Not something to worry about, and there's a decent case it's actively helping rather than just being neutral.

The thermoregulation angle matters most in your climate: sleep onset and maintenance are tied to a drop in core body temperature, and airflow that keeps skin cooler via evaporation supports that rather than working against it. In a hot, humid environment like Battambang, a low-speed fan running all night is plausibly doing real work keeping you in a more sleep-friendly thermal zone than the room would otherwise sit at, especially in the hours before dawn when temperature and humidity both tend to climb.

The other genuine benefit is masking — steady low-frequency airflow noise is one of the more effective forms of white noise for smoothing out sleep disruption from intermittent sounds (a dog barking, motorbike traffic, household stirring), by keeping the auditory environment more uniform rather than eliminating noise altogether.

Two things worth a glance, not worry:

    Direct airflow on your face for hours can dry out nasal passages and throat, which matters more given your hay fever history — if the fan is aimed straight at you rather than circulating the room, angling it away or toward the wall/ceiling is a cheap fix.
    Fans do stir up whatever dust is in the room and blow it around, so if allergy symptoms trend worse on fan nights, a quick wipe of the blades periodically is worth more than the fan itself being the problem.

Neither of those is an argument against running it — they're just the "if you notice X, check Y" caveats. The mosquito rationale doesn't apply to you since you said they leave you alone, but the thermal and noise benefits stand on their own regardless.
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