@alyx @Awoo if it's a newer (okay not even that new) drive and isn't huge then I'm guessing it's SMR. in which case you might have finally written enough total data that it has to do GC on itself. many of them can apparently become pretty unusable for a while when that happens
if you're able to, the quickest solution is to just pull everything off and overwrite the entire drive with zeros (or send it a discard command if it supports that but I don't think USB stuff is able to)
and if that's not what the issue is then at least you've got all your stuff either way
There was nothing important on it. I just pulled it out to use it for something and noticed the speeds on it are abysmal.