For me, the content created by communities that is exclusively available on that site is really helpful to me. If possible I would definitely try and archive a few subreddits and write something to search and access it offline (sorta like https://en.wikipedia.org/wiki/Kiwix but for reddit).
The topic specific dedicated communities is what's going to make this difficult for me. So, like, all of the DM focused DND subreddits. Fan communities for books that I enjoy, for games that I'm currently playing.
For general internet scrolling, so far I think Lemmy looks like it'll do the trick.
... I'm so stupid. I've been a Reddit user for over 12 years, constantly use "site:reddit.com" in online searches, have been DMing a currently 2.5 year long 5e campaign, and never once thought to look for a subreddit dedicated to DnD DMs.... Welp, here's hoping someone creates a similar community here.
Yup, there was a subreddit for every little thing. Every show I'd watch, even fairly niche ones, I could go read the subreddit after. Can't do that elsewhere really. Might happen with Lemmy in time, but not yet.