A few things that are accessible within the USA include:
- Participating in mutual aid programs
- Campaigning on the local level, including for positions like poll watchers
- Making your voice heard in community events in general
- Joining your local DSA, networking
Biden is a neoliberal centrist. If leftists vote for him it is because they have no other choice. It is why his support is so weak at the grass roots. And so strong amongst the capitalist elites. His far right opponent is a racist and crook, but runs a strong populist game. Those are our only two choices.