I honestly think we need to revive many communities related to questions, interesting topics, and overall “lets-have-a-chat-on-something” (preferably not related to what I mentioned above, or at least that touches a broader audience).

Have you subbed to the various AskLemmy/Ask[instance]/NoStupidQuestions/Out of the Loop communities across here?

To my own amusement, I found sh.itjust.works has several question communities that I tossed some posts to here & there.

Think they were:

!askshit@sh.itjust.works
!randomquestions@sh.itjust.works

And of course, the obligatory:
!asklemmy@sh.itjust.works

But besides those and the big AskLemmy communities on World and Lemmy.ml, there's:

!nostupidquestions@lemmy.world
!nostupidquestions@lemmy.ca

!outoftheloop@lemmy.world

Also although I haven't sorted out what I might want to post in them, there's these chat communities for other discussing other topics besides those you highlight getting plenty enough discussion:

!casualconversation@lemmy.world
!chatter@lemmy.ca
!chat@beehaw.org
!general@lemmy.world