I was not hired once because I didn't have React experience, despite having years of both Vue and Angular and having led teams building non-trivial apps in both. IME focusing on such a minor detail like that means either a) you're going to be so pressured to get stuff out of the door they can't handle slightly lower productivity for a month while you learn the different syntax, and/or b) the person hiring you isn't technical enough to know this is a minor detail.

Either way, better off somewhere else :)