I found a server called MinecraftOffline that runs on version 1.21.11.
It has a permanent map so your builds are meant to stay. It also uses a custom plugin suite so it is not just plain default.
The server is based in Finland which should feel good for players in Europe. It also lists its hardware like an i7-8700 64GB DDR4 RAM two 6TB enterprise drives and a 1 Gbit network.
