Out of curiosity: is Bocchi the Rock the first anime you watched that is not action-focused and has no monsters or extraterrestrial/extradimensional invaders?

As for my recommendation (but it’s really a shot in the dark, given the scarce detail you provided), there’s an older anime called “hitoribocchi something something” (I’m too lazy too look up the name) that I remember being pretty funny.

I can help too if you still have openings

In your shoes I’d do just that (booting from a usb stick and creating/mounting the appropriate partitions in the new drives)… but you might find resilvering or resizing partitions easier if you are more familiar with those operations that I am.

It must be said that actually copying the files rather than working with block devices will let you switch to a different filesystem (or take advantage of updates/optimizations recently introduced by your filesystem) or use different mount options (eg. add compression) and should in theory lead to better performance (eg. less fragmentation). In a homelab the performance difference will probably be unnoticeable anyways so… just go with the method you are most comfortable with :)

You create a new raid array with the two new disks and move the data there? I fear you’ll have to be more specific about what doesn’t add up for you…