If I see my host that I am staying at, warm up uncovered dairy in an oven and an hour later heat up covered meat in the same oven. This is the one thing I saw but In general I don’t know if this host is that knowledgeable in kashrut. May I eat there or must I leave? Thank you
Without knowing anything else about your host aside from what you are writing, I don’t think that this is reason for you to leave. There are poskim that hold that one may use an oven for milchig and fleishig at different times, and here one of them was covered so it didn’t get any zeiah or absorbed taste from the milk that might be attached to the walls of the oven. Yes there are poskim that are more machmir, but that is still not reason to say that you can not eat there or that you should leave.