I used to use Slack, but it lost its way. Arch is really, really cool, but I've become more interested in Void. Currently, perhaps surprisingly, I use Alpine because I like how minimal it is.
I loved it. No issues with the cliffhanger or it being a two-parter except for the wait time. Fantastic use of the medium fantastic story, great pacing etc.
Of the last 15 years, the only ones I really go back to are the Jump Street films and The Dictator.
I don't think any subs will stay permanently dark, their mods will be replaced eventually.
I haven't yet, but I well might by the end of this month.
It's mostly just creative automod rules, it's not that big a deal and plenty of users would come up with solutions in short order.