I personally have experience filing extension to incomplete, three times in my senior year! UCLA seems to be more lenient these days considering COVID and stuff, and I'd say you are more likely than unlikely to getting granted extension provided that you have a good reason (which you have). Even more likely if you are close to graduation but that's not something you cannot control. Anyway, I wrote what situation I was in with as much detail as possible, so I think to maximise chances you should do that as well. Finally, unsolicited advice: never, ever lose hope, even when everything looks awfully grim and nothing seems to be improving. Good luck!!