I found a modded SMP world that is already up and running with a small group. They have made some progress already so you would be jumping into an active world not a fresh reset.
It is on Minecraft 1.20.1 Forge and you play with a full mod list that they share. You can claim your own area and build your own place or you can live with the main group if you want.
There is also optional creative building but it is only for cosmetics and nothing functional. The vibe feels pretty chill and social and they want more people to join in.
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