This might not be entirely what you are looking for. However, I have created a small community where no server transfer is required. As a bit of a background I am former mythic raiding guild leader, who can no longer can commit to a raid schedule. Therefore, I have created a small in game community of players where the goals of the runs be it mythic+ or raids are about enjoying ourselves, while still trying to have some challenge in game.
The community is new and we currently have 11 members, we are still growing but many of us have played together anywhere from 4 to 10 years. It is going to be a small group of people 20-25 people maximum aiming to do mythic keys together with voice. There will be some raiding but it will be casual as most of us are a bit past the dedicated raiding time of life. So for example we might say a week in advance would anyone like to raid next friday and we’ll get it sorted, it is all about what works for the majority and there is no need to commit at all to a raid if you are busy on a given day, we won’t be aiming to do mythic most likely, I won’t rule it out however.
If this sounds like something you might be interested in, please do send me a friend request and we can discuss further.