imperialism dwarfs any domestic concerns you have
if you disagree with this then youve got american leftist brainworms
people who have shitty or bizarre domestic policy opinions but are active anti-imperialists, not in the fake "no more intervention because brown people dont deserve my help" libertarian fasc way, but in the real "hey the us empire should end" way and actually take steps to disrupt that empire are more important and helpful to the world than people who have demsoc or even leftist domestic opinions but standard or null foreign policy (this includes AOC etc)
u can do both, but one of them is required to even be passably useful
the same tiny (or great if you believe in that) effect you have over domestic issues at the federal level should be the same effort put upon international ones because the same officials are responsible for both. if your concern is "what can be done" then that same exact concern applies in exactly the same way to the domestic issues. im not gonna say "vote" or "riot" or "unionize" or anything else because while i personally fall on the "voting means nothing" end of the spectrum that's irrelevant to this because it applies identically to federal domestic policy. so once you figure out whats effective, apply that power to international politics.