I would clone the second disk to the new disk (with gparted for instance) an then resize the partion to fit the disk. This way it would be a simple disk swap without needing to do anything else.
PS: I think simply copying the files will go wrong with the hard links.
While this is a bit different than what you are asking for, there is an instance focussed on archiving subreddits lemmit online faq post. That said, I like your idea, because it also puts Lemmy out there. So that maybe more will get familiar with it. And asking a poster is thay are fine with it can never hurt.
Not totally true, the real value is combining data from different sources, but since the data they get wont have your email /ip/device/contacts etc it will be a lot harder to harvest usefully for advertising. Maybe they will figure out things to use it, but what they can use is already quite public, so they don’t really need to federatie for that
Sorry I wanted bit to fast. Clonezilla will clone disk including huid (which can mess things up is you keep both in the pc). But then you can boot clonezilla, clone disk (has a flag -k1 for resizing partitions), remove the old disk, and should work without changing anything else. If you want to change the settings anyway, there are more options like DD. For clonezilla instructions, see https://clonezilla.org/fine-print-live-doc.php?path=./clonezilla-live/doc/03_Disk_to_disk_clone/00-prepare-clonezilla-live.doc#00-prepare-clonezilla-live.doc