Honestly, if you just go through the Steve/Tony spreadsheet and add the people you want to follow that’s… basically what I would recommend at this point. A lot of people are still sorting out what they’re doing with their Dreamwidth so they may not be very active yet. Most discussion these days is basically still on Tumblr or on Discord and I am not seeing people post things like longform meta where Steve/Tony fandom is concerned – although it’s possible that people will decide to do this at some point in the future.
(I am probably going to copy over at least some of my old comics meta; I’m not sure what yet. If there’s interest, I might set up a sticky post with comments screened and anon commenting on to basically be the equivalent of an askbox, since I am aware that the majority of my comics posting here is in response to anon asks.)
But the thing about the site culture on DW is that DW gets you more of a sort of personal, journal-type view of people, so if you add people you will find that they will probably want to post about how their day was and so on and so forth in addition to their Thoughts on Fandom – and so it’s hard for me to recommend people to follow in the same way as I would on Tumblr, because, like, I don’t know if you are interested in everything these people post about just because I am? It’s a very individual thing.
The way people traditionally find each other on sites like DW is via friending memes, and it happens that there’s one running right now. Basically, you leave a comment with information about who you are and what you like and what you post about, and then you comment on other people’s comments and add people who look interesting and make new friends. (This is what I meant when I said that DW involves more interaction than Tumblr.)
In terms of Steve/Tony comms, you are going to want to join Cap-Ironman – even though there’s not a lot of discussion right now in it, it is the fandom hub and where events and so on will be announced. I don’t know if they’re planning to alter anything in response to the Tumblr changes.
Also if you like comics you may or may not enjoy scans_daily which is, yes, still going on. And as multifandom comms go, I like Fancake for fic recs. There are probably more things I am not thinking of.
The other thing you might want to consider on Dreamwidth, for about the next week or so, is signing up for Fandom Stocking, especially if you are a fanwork creator. It’s a low-pressure fandom gifting event where you sign up with your favorite ships and pairings and then people just… make you stuff. That you like. People will also leave you non-fanwork gifts that you might like; people ask for recipes or pictures of kittens or holiday greetings. A lot of us in Steve/Tony fandom typically sign up for this, and we just… try to make a lot of Steve/Tony content. It’s fun. Their signups close on the 15th.