So sorry to read that your wife is now back in the tunnel of depression once again. I do not think that she faced and resolved her issues and it's going to take her some time to do so, if ever. She didn't want you to move out and she was able to maintain some clarity for quite some time. Hopefully, once things settle down and we get into the "new" normal routine/mode, she will have a bit more freedom to get out there and just breathe once again. So much going on around the country and the world right now and she may be feeling a bit confined and feels the walls closing in.
So, what do you do? Get back to the basics and just leave her be.
Please take care of yourself.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.