I went through this for about 3 years after my divorce. I couldn't find motivation or joy in anything. I turned to helping other people solve their problems because at least I was helping others to get through what I couldn't figure out how to get through myself. There was a lot of time spent in reflection and introspection and about a million cups of tea drank while looking out of the window trying to will myself to do something, anything. It was a tough run, I was just dragging myself out of it when COVID hit and kicked me while I was already down. I think I'm just beginning to be back on the rise again now. I can't promise I've got any advice that can help, but it certainly sounds like you are where I've been.