Shutting it down from Reddit’s end won’t work here. Reddit open sourced their server code a while back, and this would allow people to point now-banned reddit

Shutting it down from Reddit’s end won’t work here. Reddit open sourced their server code a while back, and this would allow people to point now-banned reddit clients at third party servers running an open source reddit fork from 2017. The main change from then, according to TFA, is the new UI, but you still get the equivalent of old.reddit.com if you move your subreddit to this (and your members would then be able to use third party clients, assuming this proposal succeeds).