YSK: You can use wefwef.app (Voyager) to import your subreddits
Recently wefwef.app added an option to add the link to all of your reddit subscriptions (multireddit link from old.reddit) and search for replacement subs. You can pick which communities/instances you want to subscribe for each sub.
You should know this because it can make your life easier if you want to search for communities you're familiar with.
Over a decade on Reddit makes this a multi-day slog. It looks quite useful, but I've spent the last month moving into Lemmy. I'm using the same strategy here that I used there: search for the basics, subscribe, read, and if anything interesting mentions another community, subscribe on the fly. (Of course this strategy is probably why looking at Wefwef's migration is overwhelming.)
Same. I’m ‘all-in’ when it comes to Lemmy, but I only subscribed to a dozen subreddits I remember enjoying, and that’s it. Now I simply either sub to a new Com when I stumble upon it, or search for it after remembering a specific subreddit.