I would say just don't bother with reddit, but Sino is probably the best China subreddit. For the love of all that is holy stay away from /r/China, I am pretty convinced it just consists of sexpats with a sprinkling of diaspora that have never actually been to China. Sino isn't explicitly a communist sub, but that tends to follow it being a relatively pro-China place to begin with.
Genzedong was great, but after the quarantine has largely migrated over here. I think some people still post there.