I know a little about the academic system. it's not an easy market to succeed in. but if you do it's a wonderful life. you're free to work on problems you find interesting, without worrying about whether or not they are profitable.
sounds like you genuinely love doing research in math, given that you put in a lot of time and voluntarily turned down a cushy job.
my suggestion is to put your nose to the grindstone and pass your quals. it's not easy and not everyone makes it... but it sounds like the path to the career you want is this way.
i hope this passes and execs get harsher sentences than the just stop oil protesters.
however the people making the laws and working hand in hand with the people polluting. sometimes it's blatant bribery. sometimes it's a mutually beneficial agreement that comes at the expense of the environment, and the rank and file worker.
so I don't have much hope of the laws passing, or big polluter execs getting actual jail time. but I'm happy to see them trying
i used to use zfs for backups via snapshots. but I find using rsync and hard links is much more convenient. i can use standard tools to look through backups and track which files changed if needed.
does it run Linux? I'm waiting for a good low power CPU laptop that I can install a standard distro on. preferably arch...