Probably its part of Flatpak?
The same amount of JXL gives you more image than JPEG? Also, it supports ridiculous resolutions (terapixel).
I took my existing JPEG file, compressed it using JXL, 15% smaller.
Then I decompressed it again into JPEG. The file was bit-for-bit identical to the original file (same hash). Blew my mind!
Directly using JXL is even better of course.
Without UEFI, the boot process is different for each device, requires a custom boot loader, or at least explicit support by the operating system. Is your laptop going to be supported by the distribution you want to use? What about in 5 or 10 years? With UEFI, the boot process is standardized, so it should just work.
Are you sure that it cannot be updated? The GitHub readme sounds like updating Tiny11 Core is impossible (and it also lacks Windows Defender), implying that Tiny 11 can in fact be updated.
Then the editor, all extensions, language servers, etc. are all running as root.