@Mark3465 I would have some doubts about the people who choose to stay in a shared home with a stranger while a pandemic is spiraling out of control, but I do see plenty of posts from similar hosts who are still having positive experiences.
One thing that has always been the case, though, is that longer-term guests treat the home much differently from short-term holidaymakers. Behaving more like a flatmate than a guest is common, though stealing alcohol is way out of line. What was your communication with these two guests like prior to accepting their bookings? What was it about their correspondence that made you feel confident that you could live with them for months?