Just say to have it 30 mins later or whatever, problem solved. Come up with some excuse, or don't say anything at all. And then have the meeting and be as effective as possible during it. Cut bullshit meetings to a minimum. If you have more than 6 people in the meeting and you're not essential, don't attend. If you have meetings longer than 1h, try to go through the points as effectively as possible and underscore the conclusion dor each point until you get a resolution (important, so you don't get invited to _another_ meeting)

I am talking from experience here, not just out my ass. I can't imagine how it would be remotely sustainable with two full time jobs, nevermind more than that.