I have a small external backup drive where I dump my phone camera captures and archive YouTube channels - nothing special; a few terabytes, mostly mp4s.
Is there anything I need to do before/after I swap?
If it matters, the drive is 9TB, formatted as NTFS, and connected via USB 3.0.
I also have 4 internal drives, but I’m not so much worried about them, as I plan on just formatting everything but the external.
I shudder to think what you consider big.
Anyway, you won’t have any issues with it, but if you’re going to use it for any length of time and not go back to Windows, I’d change it to something like xfs or btrfs. Hopefully it’s less than half full so that you can just shrink the partition, create a new one, move the data, delete the old, expand the new. If it’s more than half you might need to do it in steps. If it’s basically full, don’t bother because it’s more trouble than it’s worth.
I second btrfs. Even when I was sharing with Windows I used their btrfs driver and it worked fine there too, but I had to occasionally make my user the owner again booting back into cachy, so now I just dont share drives and relegated Windows to a small 120gb SSD for emergency use only.