I went with Nvidia and I never really had any issues on Linux with it (I only use Linux).
AMD might be better on Linux out of the box in the sense that you can just install whatever distro and it’s going to work and with Nvidia some distros will require to install the drivers yourself or tinker one time in the terminal but it’s really not that big of a deal
But go with whatever you think is best for you.
Yes I have to switch to light mode everytime I go outside during the day because (unfortunately) my screen just isn’t quite bright enough in direct sunlight but switching to light mode helps me see things a little better.
But normally I prefer to be in dark mode. It saves battery (I have an AMOLED display) and is easier on the eyes especially indoors/in dark environments/at night.
If my screen was brighter I’d leave dark mode on when outside in direct sunlight too.