May I ask what made the followers look advanced to you?
As we've progressed my perspective has changed! Back then, when you're at the bottom and know very little, everyone dancing at a milonga looks better and 'advanced'. To a very limited extent we knew walking, side steps, cunita, cross, fwd & bed ocho, giro, and ocho cortado. Not well! And not well executed! Sufficient to get around. Sufficient to string together (a useful recommendation had been to regard the dance around the ronda as a 'string of pearls' - walk and put in an occasional 'pearl'). We had also learned a little of
abrazo - 'close' versus 'open'. Despite experience of dancing previously with different women (and my wife with different men), 'close' hold with many different women was, then 'perturbing' as a male. Also, early on, I'd had a 'revelation' about leading! Back ochos, I think. I could walk with a follower, and then, if I moved my upper body correctly, I could lead back ochos, and get out of them!
'Advanced' (as distinct from 'professional' teachers, maestros) could dance effortlessly and smoothly. Followers added adornos. There was intricate leg 'knitting', ganchos and leg wraps. Followers usually looked and dressed the part. PYTs were usually underdressed in comparison but could perform intricate, complex moves - which I had no idea how to lead. Invitations were still a bit of a mystery. Obviously many were invited verbally and knew their dance partners. It was a social scene. There was some cabeceo/mirada. Was I doing it correctly, or just being ignored? We knew enough of the structure to know of vals and milonga, but avoided them at that time. 'Advanced' followers could dance those as well! It looked good.
We were lucky. Our first milonga (not where we took lessons) was friendly and welcoming. People talked to us. We were invited to dance (me too!). And then we found the same people at other milongas. We also started to find that some were not as 'advanced' as we thought. Some had a limited set of elements and their 'routine'. Others couldn't lead that well. Some followers just wanted a support for adornos.
And then there were, sometimes, the 'sexual' politics. Dual-role wasn't new. I'd previously, sometimes, danced the 'lady's' steps. My wife's previous 'coach' was gay. But then we had the lesbian couple (one in 'male' suit; one in very 'female' dress). Also the female leader. Dressed the part, and occasionally turning up with a few younger, very well dressed, younger women (PYTs), who only really danced with her - they didn't respond well to invites from ('advanced' male leaders).
Where we started to learn took the view that after 2 years of learning to walk, then maybe(!) we could consider going to a milonga. We were fortunate that the teacher left and others took over. We also had the advantage of attending other tango group classes in other places (family circumstances meant we could be spending weeks in London with AT groups within walking easy distance).
So, from a 'beginner' perspective, the milonga was scary. I suppose we also visited 'practilogas' which were more relaxed.
So, years pass. We take private lessons. We do workshops (I used to ask in the early days whether we knew sufficient to do the workshop). We take courses. We go to prácticas. We take a few tango 'holidays'. We also look out where we could dance when we travel - so over the years have danced, and taken lessons, in many locations in different countries throughout Europe and further afield.
I'd say we were now forever 'intermediates'. There's still lots to learn. A dance partner is useful. As someone told us visiting a very 'elite' milonga (lots of teachers and a performance from some highly rated Argentinians): 'At least you'll be able to dance with each other'. They were correct there! A solo follower nearby got no invites all evening, not even from the table where she sat. (Many tandas were bring arranged in the drinks area!). Met her at another milonga the following day where she got many invites. And being a 'couple' at some milonga types, usually where unknown, is a disadvantage if you're objective is lots of dances with others. Acquaintances, who are regularly in BsAs, tell us they have to go separately to get dances.
Recently my wife and I were practicing some vals cadena at a práctica. I invited a novice follower to dance afterwards. She looked at me in horror and said: 'I can't do that!

'. We had a good dance

.
So I think that categories like "advanced" and "beginner" are not always helpful in tango. Sometimes an "advanced"-"beginner" combo can work amazingly well, much better than two dancers at the "same" level, whatever that's supposed to mean
Beginner, novice, intermediate, advanced... are more helpful than level 1, 2...6. They have some uses to teachers. Just don't measure it by elements you can perform (with a partner) or some certificated qualification.