> "I've searched high and low, and I found that x86 laptops improved a lot, but the screens barely reach 500 nits most of the times, which makes working outdoors a very unpleasant experience."

Wondering if you've compared different types of anti-reflective coating (i.e. "matte" vs. "glossy") of screen? I suspect a leading-order variable isn't how bright the display is intrinsically, rather how effectively stray reflections get excluded.

The best display in direct sunlight I know of is an e-ink screen, and it's 0 nits!

This is one of those questions AI is actually useful for. The Lenovo Thinkpad P16 is officially linux-supported and one of the few that exceeds 600 cd/m² maximum brightness when optioned with the 4K panel.

My source was this tool by RTINGS: https://www.rtings.com/laptop/tools/table

The Stellaris 16 by Tuxedo Computer can be had with a display capable of 1000 nits when used in HDR mode. You can read more about it in the 2nd option under Display / Monitor section here: https://www.tuxedocomputers.com/en/TUXEDO-Stellaris-16-Gen7....

Alternatively, consider running Asahi Linux on your MBP?

Depending what you're doing, this runs Microsoft Office, Obsidian notes, Chrome, or most anything else that runs on an Android tablet:

https://daylightcomputer.com

Add a bluetooth keyboard with a groove to hold the tablet in landscape, and you have a laptop when you need one, or an outdoor e-reader/e-ink tablet when you don't.

Even more natural light oriented (this has no backlight), but not as computery:

https://supernote.com/pages/supernote-manta

(I wouldn't attempt to use this as a daily driver, it's just nice outdoors, perhaps the best of the note pads and the unofficial Kindle app works in landscape giving two paperback book side pages side by side which feels extremely natural to read.)