Hey! You sound like you might be a great fit for our guild Impaired, we are a relatively new (6 months old) Alliance guild on Ravencrest EU. We are currently 6/10 Mythic Castle Nathria and have a few select spots opening up on our roster preparing for 9.1. Our current goal is at least 8/10 Mythic Nathria and then Cutting Edge next tier. We are a more mature guild with most of us having played the game since TBC/Wrath, a lot of us having even played together most of that time. We actively try to run Mythic+ with the majority of our current roster having Keystone Master.
You can read more about our guild here; New 2 Day Raiding Guild - Alliance - Ravencrest. If any of this sounds interesting to you please get in touch with any member of the guild in game or message Brukerr on Discord Brukerr#1325 or Battle.net Brukerr#2705.