I generally prefer actions that undermine systems of oppression while also helping people. As you point out we aren’t in a position to militarily defeat the government or anyone really and honestly I’m not even sure that’s desirable anyway. Maybe I’m naive but I choose to believe that the world can be changed nonviolently.

So things like mutual aid, working in your community to plant trees, build organizations and infrastructure that directly help people, etc. On the more confrontational side, political marches and rallies, especially when organized as a sustained pressure campaign that targets specific decision-makers with specific demands, civil disobedience that directly makes it harder for the agents of oppression to do their work but that doesn’t harm the general public.

In the current context, the best actions are those that raise awareness and build sympathy for your movement while also reversing, slowing or stopping harm.

I know that’s a little vague but I think there are many activities that can contribute. So find your people and your niche and get to work. I’m just starting out in this journey myself so I’m sure I have more to learn too.