Hi Roswaal,
It seems like Supercool Discotheque could be the casual guild you are looking for, We are an Alliance guild on Ghostlands that do mythic + runs during the week and raid on a Sunday evening. If you think that is something you are looking for please send me a message on Battle net wolfus#1389 and i’ll get you added to our discord 
Please see this post if you would like more information: [A] ghostlands-dragonblight <supercool discotheque> Casual 1-night-raiding