Seriously, free speech zones are a mockery of the Constitution.
Unless we are in red flag fire weather, you should be able to burn your flag wherever you please. If we’re in red flag weather, I politely request you, I don’t know, paper shredder the flag?
How did you get 325? There are 435 members normally (433 assuming your numbers are right with vacancies, which seems believable.) 2/3 of 435 is 290.
So you’d only need ~78 republicans with morals. Still wouldn’t happen, but weirder things have.