Firefox is also really good on Android these days. I use that with all the usual ad blocking and privacy extensions I have on desktop.

ALVR works great, assuming SteamVR in general works with your DE (no Gnome support atm but KDE works for sure).

Since you mentioned darktable I assume you already know this, but depending on the camera’s raws and the presets that imagemagick has for converting these photos the results might be undesirable if not inspected or tweaked. Not disparaging any advice given here, just mentioning that generally raws are edited on a case by case basis to fix camera artifacts and color issues. Hope the solutions others have posted work out for you!

There are different reasons to support alternative browsers. While Firefox on IOS definitely does ad and tracker blocking (which is great!) Some people are concerned that the underlying engine is restricted on IOS to webkit. So it may very well be a better experience for you than safari, but that alone does not satisfy concerns of homogenization in the browser space on Apple devices.