Something is still wrong. I tried resetting all bluetooth and wi-fi on my iMac, iPhone, iPad Pro, and iPad mini. All are on the same account, same wi-fi, with handoff turned on.
I also turned off my TextBlade, just in case that was a factor. I did get a couple successes (though none with the iMac), but mostly it just didn't work. When I'd try to paste, I'd just get whatever was last copied from the same device rather than the item I copied from a different device.
I do remember when I first turned "handoff" on with my Mac, I got a popup which talked about turning on "sharing" screens and files. And I did that, which was when I had my first success yesterday with the mac. Then I turned those two items off and it still worked. Well, it never worked well, but it did sometimes. But even worse today and that's hard to do considering how bad it was before!
Oh, and my devices I'm trying to copy between are quite close together and also close to the wifi router.