It would require acting outside the confines of the law, because fascists aren’t bound by the law either. And the more the US government is made obvious to be a joke, the more people might finally get the fucking clue that institutions are meaningless when they don’t actually enforce the rules or provide meaningful support for what the working class actually needs, and they might eventually decide to do something about it.
That is, of course, hopeful thinking on my part, but I think it’s the only correct answer to “what can we do when an overt fascist has power”.
Additionally, on an interpersonal level, you need to find communities IRL if you don’t have them, and be defiant together. Don’t let these evil fucks normalize anymore bigotry or conspiracies than they already have. Even if social norms would dictate otherwise, call that shit out when it happens.
And don’t preemptively give up or resign your position if you hold some sort of influential role in society. Don’t make it easy for them. Every single bit of defiance makes it that much harder to impose the hell which they intend to inflict, which is in and of itself valuable.
The closest that you can get is using something like Grayjay, where they have their own social media system, but your comments will only be interactable to other people using Grayjay.