What time were you playing at? I’ve been very slowly leveling an anniversary character on the off chance Blizzard actually will make a TBC Era server. I’m level 21 and have had no troubles finding DM groups. I haven’t looked beyond that, but if you’re having troubles finding even that then it makes me wonder if you’re playing an off day.
Definitely lots of advertisements and the whole of Anniversary is a FOMO driven mess, but even when Era was at its worst for that you could still find groups. You’d just have to build them yourself and reach out to folks.
I promise you, you’re not the only one who isn’t interested in pay to play gameplay.