For now, trifold are a gimmick, the screens break and the hinges get full of dust.

It's yet to be seen whether a trifold can be made into a similar folded size as a non-fold phone with similar capabilities, but even then... the resulting unfolded phone would need to be about 1/3rd the thickness of a normal phone, which is a lot to ask; by the time the technology is there, normal phones will be 1/3rd thinner too, so a trifold will again seem "clunky".

Backpack phones, is what we call "laptops" nowadays, some come with 2 extra monitors, or you can add them as an accessory.

Android phones can run regular Linux via Termux, and starting with Android 16 they'll come with a regular Linux VM with GPU acceleration support.