I'm not sure it's even possible to contain some of the tropes. I still occasionally see people posting "first" on YouTube and similar, and that's a Slashdot troll meme from more than 20 years ago.

I am really worried it will be an uphill battle. I see two things happening 1) We all exodus here and ruin this place. 2) Nobody cares and just leaves Reddit doing what it wants. Sadly neither are great outcomes, and yes I know I am cynical.

To complicate things, you may also get different behaviour in different communities by the same user.

I think it's really at the community level that culture can be formed as at the all post level, we all just have our different preferences and that's fine. Also, our preferences may changed based on what we want/need in a day, e.g., one day we may want jokes while another day we may want tech support.

And so at the community level, community owner Bob may want no low-effort posts so he can put that into the rules, the mods can enforce that (be removing low-effort posts), the community can enforce it by only upvoting high-effort posts, and then a culture is formed which will draw other people who are into that.

And likewise the same for other culture/expectations.