Use the wider community to keep the interaction alive.
If there is an event discussion, photo recap or normal community conversation afterwards, joining in gives people a reason to recognise your name again.
That is often enough. You do not need to turn every good conversation into a separate one-to-one friendship immediately.
Choose another plan before deciding the first event failed.
One event mostly creates recognition. The next one gives you a chance to continue a conversation without starting from zero.
You do not need to attend everything. Pick another format you would enjoy anyway so making friends is not carrying the entire reason for going.
Remember one or two ordinary details and let familiarity do the rest.
If somebody mentioned a game, place, pet or plan, remembering it next time makes the conversation feel continuous.
The useful thing is the feeling that you have met before, not proving how much information you retained.
Let different friendships move at different speeds.
Some people click quickly. Others become familiar faces for months before the friendship gets deeper. Both can be real connection.
A community becomes valuable when you have multiple chances to reconnect instead of asking every first conversation to produce a best friend immediately.