I found a small closed beta vanilla Java server that wants a few committed players or small groups. It is survival focused and the progress is meant to take a long time.
The main point is testing long term stability while you actually play and progress. They want people to notice weird behavior soft locks or crashes and also see how things interact with custom code. Some mechanics are kept secret so you can discover them.
It is whitelist only with a small tester pool and it may be a bit harder than normal survival. The server is hosted in US West but they said anyone can join if they are fine with occasional instability.
To get in you have to do a short voice chat intro before you get whitelisted. Scheduling can take a bit since it depends on when both sides are free.
