A tablet form factor with a documented electrical interface for magnetic attachments (like an MS Surface style keyboard) that can run Android or Linux, or be repurposed for embedded or IoT touch interfaces.
A NUC or Raspberry Pi type device with a beefy AMD SoC inside, with optional battery support. Maybe it's thin and light enough that it could have snap-on touchscreen and gaming attachments that Lego together into a custom Steam Deck.
A solid TV without any built-in advertising junk, maybe running Android. The chassis, display panel, controller board, CPU board, and remote control can be purchased separately, of course.
A sleek and repairable smartphone where you can even replace the stock Android with Linux, where all the peripherals are documented and have open drivers, so with the right software you can have a Linux phone that doesn't suck.