The lowest brightness levels often have very poor contrast levels and will cause more eye strain as your eye will have a harder time discerning what’s on screen.
Additionally at lower brightness levels you may have higher flicker on displays due to PWM.
It makes sense to work at a brightness level that is appropriate for your environment. If your screen supports ambient light detection, enable it. Ideally you don’t want your eyes to constantly be shifting between brightness levels of your screen and the world around it.
If you do have eye strain, make sure to take regular breaks and excercise your eye by focusing on things at different depths. That has been shown to help push presbyopia to later years (but nothing really prevents it)
Also HDR colors are NOT best at maximum brightness. It’s a common misconception because humans react better to brightness. It wholly depends on your display technology , but color accuracy and depth are not linearly related to brightness and often have a falloff when you get to higher brightness unless you’re using an OLED display.
In color accurate fields, monitors aren’t set to highest brightness. Colors are calibrated against a standard Nit value which may be lower than what the monitor displays. Above and below those values, your colours are often going to be wrong compared to the intended content.