Interviews are much more of an art than science and asking good questions is hard. In general, they should be open-ended and get people out of their comfort zone to avoid canned answers. At the same time it's an interview, so you will want to leave on a positive note.
My advice would be to think of what is important to you at work. Then research about the company (maybe also by talking to current/past employees). In the interview, carefully probe for any red flags to confirm your suspicions. Personally, I'd go for things like work/life balance, WFH and career progression due to Covid, but that's very much up to you.