Yikes! I have a similar dilemma with a Samsung external drive which has most of my data on it, as an in-house backup. Well, when I used the PC it did. Now I mostly use the Mac or iPad that data isn’t exactly available as it’s formatted NTFS. There’s around 750Gb on it. Do I just purchase a new 2TB drive & format so Mac can use it. Then copy the data across. Or do I copy all of it back to the PC (if there’s room) and reformat the one I have. That said, most of it is duplicated on OneDrive but not all. I’m starting to lose track of what is where… Not to mention the two flash drives I have on the MacBook, though they are backed up to iCloud. I was using Arq but with Amazon Drive. That got expensive so I moved it to OneDrive but haven’t let it do a full backup since.
I think I’m getting old - & more easily confused than I used to be!
At least I haven’t lost data yet, other than most of my contacts when I deleted them all from Google believing them to be in iCloud. I turned off Google contacts and they were all on my phone. When I deleted them from Google they suddenly weren’t on my phone, despite having disconnected it from Google. Baffling.