Beginner asking for guidance and advice

Hi fellow WOWers,

I used to play Retail WOW about 10 years ago (5.4, 6.0...) and want to try this out. I know people loving this Vanilla experience, but just wondering if it's hard to start without ever playing Vanilla or classics. Is it slow to level up or find people for dungeons without the "modern" dungeon matching or meeting stone? If yes, what's the best approach?

Thanks!