No. The entire point of the Fediverse is so that no single site can monopolise discussion on a topic. Having multiple communities with overlapping themes is an expected and desired outcome.

And, to that point: the themes are indeed merely overlapping in this case, not identically the same. 'ask gaming' is about asking questions of the gaming community. 'let's talk...' lends itself to more in-depth discussions. They are not the same. There can be no justification for shuttering one in favour of the other.

People keep trying to force there to be 'one single comm to rule them all' for each given topic, as if this is reddit or something. That's literally the exact opposite of the point of the Fediverse.