I live in DC, and I can have access to key people. I am clear what is my goal for this next decade. I want to build and maintain a professional network in DC and in my original country. I don't want to just knock doors. I want to strategically know the people to reach, what is the WIFIIT for each network group, and how to maintain the network.
The best networking is slow-cooked, not microwaved. Find events where you can have some kind of regular presence.
Got nothing to lose by going to one-time events as they're good practice for meeting people, but you won't really cultivate long-term professional relationships that way.
It takes time which relies on that regularity aspect. Build trust and don't look at networking as a transactional thing.