I'm curious what exactly MTG should be doing instead? I mean, let's assume not being some christo-fascist isn't an option, because clearly that isn't in her case.
Do a thought experiment with me. You're someone with an outside the mainstream political ideology representing a district where the voting base is also outside the mainstream. You're in Congress, but you really don't have the allies and the numbers to actually advance any of your agenda items. What do you do with your time?
Grandstanding and making the case for your fringe political position, in hopes that you can sway others across the country and elect similarly minded colleagues (or flip existing members) is probably as good of use of time as anything. If you have no real power, PR stunts are not a terrible way to try to do the yeomen's work of building a political movement.
Much of the same analysis could be applied to people like AOC. Do big flashy stunts, get your political message out there, especially in contrast to the mainstream that people are increasingly losing confidence in, and hope that in 2,4,8 years it pays off in the form of more likeminded congresspeople on your side. In time there might be enough of your to actually have legislative leverage as a "wing" within a party, or even become the dominant wing within a party.
My problem with MTG isn't so much her PR stunts, which seem like a reasonable way to approach her current predicament. My problem is that she's a fascist and the political project she is advocating for is fascism. Which is bad, but let's not confuse bad politics with bad tactics.