I really sympathize with the OP. I basically lived in dungeons during Vanilla/Classic Era and TBC.
But this is exactly what happened when OG Wrath was released (sadly, IMO). Dungeons (especially Heroic) went from strategic CC and coordination to face-roll AOE-fests in a day after Wrath came out.
I still remember my first Wrath dungeon when the DK ran in and AOE’d everything until the end, everyone just blew up everything in 20 minutes. That was par for the course for all dungeons, basically from then until present day in Retail. (Blizzard tried to make dungeons challenging again at the start of Cata but people protested and the dungeons were made easy again - and they’ve been AOE face-rolls ever since.)
My suggestion would be to reconsider returning to Classic Era and find a guild. I was pleased to discover there are still many active guilds to choose from. They were at various phases, even. Some restarting from the ground up and beginning MC and others farming Naxx. But all seemed focused on honing their craft and enjoying being in the World of Warcraft - rather than face-rolling through it, as the Zoomers and the cool kids are bent on doing today - even in Classic lol.
LOL, I know I sound old saying this. But I can’t believe I have to state the fact that this is an old, old game that hundreds of millions of people have already played. And one of the main reasons people asked for Classic to begin with was to return to WoW to enjoy it - especially after so many face-roll, soul-less Retail expacs. But now, here we are, face-rolling our way through an old game as fast as possible with 50% XP boosts and Characters boots galore. But I digress.
Anyway, you can look around (on the mega-servers, like Pagle/Makrik/etc.) and see which guilds are popular and join their Discord. (There is little activity in the LFG channel.) But with a guild, you can still do dungeons the old fashioned way. You’ll have to settle for raiding in Classic though for better or worse. Raiding used to be only one aspect to this game, contrary to popular belief. (When I played Vanilla, only the minority of players I knew actually raided). Classic Era is tragically a different place now as you probably know. But while it is sparsely populated, I was surprised to discover you can still find active guilds and Discords that compete with the same number of members as today in Classic Wrath/Progression. (I just finished researching the active guilds on Pagle). They will do dungeons with you. And during peak raid times, Stormwind was pretty busy. Best of all, the PvE is essentially the same: coordination/communication/strategy. It’s so much more interesting than the AOE face-rolls, I would agree. I hope they offer TBC again for these reasons.
My only hope for Wrath is to jump in and run like everyone else a million miles per hour through the face-roll dungeons and maybe find that the end-game raiding in Wrath (which I never did) will present some challenge like TBC did. But, maybe I’m just being naive.