Hubzilla, for example, has a UI that's largely stuck in 2012.
This is also why I find the western Misskey forks' desire to pander to mobile users by trying to function with existing Mastodon Clients so counterproductive - the Mastodon Clients often just don't care. They really only are for Mastodon and everything else is "good luck have fun".
Frontless servers to me are a bad idea, as things stand - despite the appeal in speeding up initial development.