It’s Zeus and company antagonizing Hercules, not Michael Burnham being central to solving five (?) entirely unrelated but galactically significant disasters, apparently by pure chance.

Yeah, there's a lesson in good writing right there.

I think another way to approach this is demonstrated in The Expanse series and in a lot of Captain America stories: after you save the world, more big world-ending events get brought to you by people looking for help and enemies looking for revenge.