Comment by bell-cot

> You're going to have to either...

Yep.

And even if there are no technical grounds for firing, HR and/or a few higher-up managers should hear about the problem from the direct manager (you), and know that you're looking for solutions.

And from "the last few months", I'd say those conversations are overdue.

Might your jurisdiction be one where being fired is a better deal (gov't benefits, whatever) than resigning?