Just noting because I went through the same, but I haven't found I've been able to use any LCD or OLED at very low contrast and brightness without content becoming illegible or uncomfortable without ambient light. However, a relatively smaller CRT maintains a contrast ratio that I don't seem to struggle to look at or decipher in complete darkness.

I've also tried dropping the aspect ratio on my 42" 4k OLED to 4:3 and not scaling the resolution to limit light output, but the pixel density ultimately seems to be a limiter. Since I can work on my smartphone at its lowest output and with redshift, a smaller, higher-dpi display may be key.

I have a 'study' setup using a Boox Mira (portable 13" eink screen) for exactly this kind of use; not polyphasic in my particular case but late evening use. Yes, the screen is expensive, but _totally_ worth it.