I found this server called Chilltown and it feels really calm and relaxed. It is a survival SMP that tries to stay close to vanilla but without all the usual chaos and drama. The world has been running for a long time and it has grown in a natural way with towns farms and different player projects.
Chilltown is made for people who like to play survival at their own pace. The community is mostly adults and everyone is respectful so it feels pretty safe and chill to play on. It is also good if you are tired of pay to win stuff or servers that reset all the time.
The world is not just random terrain. They use a custom world that looks really nice and there are seasons that change how everything looks. There are custom mobs weapons tools and enchants but they are balanced so they do not feel super overpowered.
You can protect your base with simple chunk based land claiming. New players get a starter kit and daily rewards so it is easier to get started. There is also an optional tutorial if you want help learning how things work or if you like playing mostly solo.
The server runs on Java 1.21.11 which is the latest version in the post. If you want a place to relax build and stay for a long time Chilltown seems like a good choice.

