The "Unofficial gRPC Community" Discord server
from the last discussion was essentially a failed experiment. People joined, but there was not a
single discussion. Gitter actually has some activity, so it isn't dead but rather pretty quiet. People ask plenty of questions, but only a few times over its life did users answer each other's questions. GitHub discussions aren't enabled on most repos; I enabled them last week(?) for grpc-java. It is something that we were going to experiment with, but mostly as an alternative to issues and the mailing list.
Part of the trouble is Germany and California have quite the timezone difference, so like the complaint "people show up in 12h interval" in that last thread is just saying "people aren't in my timezone." I definitely agree that is the case, but there's not much those of us in California can do about it.