Would you do a postdoc at a place where the faculty mentor's research is only very tangentially related to your own research interests? I'm in pure math. I'm in the situation where I have to decide whether to accept or to try again. I was discussing with someone and he said, "Who cares if your faculty mentor doesn't work in your area? Now there's Zoom, there's e-mail. I collaborate with people who I haven't seen in person in years."
But the postdocs I know are working with mentors more closely, writing papers with them, etc. In grad school I felt pretty isolated and it was much harder than it could have been, because I had all these questions that my advisor couldn't answer, and e-mail responses I got from other professors weren't very helpful. If I do a postdoc, I want it to be productive. I think that in order for me to be productive, I need to be able to bounce my ideas off more knowledgeable mathematicians in person. Right now my approach is, when I read a paper I think of some natural questions, but I'm not discussing them with anyone.