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.
Aside from having it disconnected while you are formatting or installing to be safe, you should be able to use it just fine.