Suck it up, go to Ascension.gg and play the game. There unique leveling mechanics aside (which would be awesome), they have scaled classic raids (3 levels of difficulty), mythic+ in classic, and a variety of customization options that make endgame WoW Classic not only fun, but endlessly challenging and rewarding. They have Arenas…in classic, great active pvp…a world pvp mode with unique loot…in classic. They also have an Ironman and Nightmare mode which essentially create a solo -game feature which are very fun. I think this will get you closer to what people want, because “Season of Mastery” is not it…its a fair bit of terrible.
With new ownership, you have achance to EMBRACE private developers and people who love the game. Hell, hire them to run various types of Classic servers. Give your players tons of options on how to play and watch your subscription (and vanity shop - the real money) revenues skyrocket.