This has been the case since android 6. It just didn’t show you that message and would simply refuse to update non-play store apps.

Depends what version of the Surface, but I have a Surface Pro 6 and it still performs well. I use the Surface Linux kernel.

The trump comments aren’t the issue, it’s Proton’s acknowledgement that they will turn over data to the swiss police when asked.

BTRFS and ZFS both use block compression, ZFS by default. It’s meant to increase both storage efficiency and access speed and has nearly zero impact on performance. The files aren’t compressed from the filesystem point of view, which would satisfy your requirement not to need any other tools.

I’m confused about your statement that you don’t want to save space with compression, but you indicated that you want to “make the most of your storage”. Are you looking for long-term archiving?

It’s not clear here if you mean block compression, file compression, or stream compression.

It would be nice, but the time it takes to do the work of validating package versions for LTS candidacy is either limited or not free, so this is the acceptable compromise.