I looked at the comparison for Seafile as that’s the one I’m most familiar with. In my opinion Seafile’s greatest strength is its encryption, but in your comparison you seem to see this as a negative as I assume this bullet refers to the encryption? “isolated on-disk file hierarchy, incompatible with other software. much worse than nextcloud in that regard”

Perhaps Eco. It’s a bit like Minecraft but much more farming, if you choose the farming profession, and no combat whatsoever. Mainly a multiplayer game through public servers but it’s doable solo as well through settings.