I'd add that running in HDR mode should be fine as the brightness is controlled for SDR content using the Windows SDR slider. Since OLED can do per pixel dimming you will have a similar brightness to SDR if you adjust the display for that using the Windows slider. I measured that a 7% value on my display gave me the 120 nits I normally use. So with HDR even though the setting for OLED backlight is at 100 it does not mean those pixels are running at 100% brightness unless watching HDR content and even there it will vary a lot.B6 user here. I can safely say that running the OLED backlight at too high will cause long-term wear problems. I'm running at 30 now, where I used to run at 100. As for static content, as long as the backlight isn't blaring and you don't have a UI up completely uninterrupted, you should be fine.
But for desktop use it's generally best to go for low brightness.