A great resource on Universalist Christianity: universalistchristian.net.
Aside from DC’s Universalist National Memorial church, I don’t know of other historically Universalist churches that still practice UC explicitly (of course people are still theologically universalist individually). Many (most?) Universalist churches morphed into Congregationalist or Unitarian Universalist (or Federated, possibly Baptist) churches…or closed (eg www.oldhousedreams.com/2018/12/1…).
If there’s a list of active UC churches, I’d love to see it.