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
While I think it’s important to vote, the user you are replying to is mostly correct. It’s just important to understand that “direct action” isn’t the only viable domain of activism or civil engagement.