1c: Firefox profiles are fully portable to any other Firefox install.

I knew they had an export/sync feature, but does it include stuff like browser history as well?

1e: Nothing. It doesn’t touch any of your filesystems unless YOU touch them. Don’t delete anything, and you’re fine. It should even automount your existing identified partitions for you to browse through.

I was mostly afraid of deleting something by mistake since I don’t know much about how the commands work, but by your reply I assume it’s not something easy to do unintentionally (?)

2-3: I wouldn’t even bother trying to figure any of this out, because Microsoft constantly changes their mind about this, and they’ll soon just force you into this abomination of Windows 12 they’ve been talking about recently.

Yeah, I’d avoid doing that too, but I have a lot of hoarded stuff and might still need a windows partition in case some of my friends really want to play something with anti-cheat. Of course, even if I do end up going the LTSC way for the main pc, I’m still gonna try and learn Linux at the same time on the secondary one, I know it’s just delaying the inevitable.