At my kyokushin karate dojo, one of the instructors is nearly 80. He's physically incapable of performing most of the techniques he teaches. Like, one of his knees doesn't really bend anymore, so he can't even kick at all. But he still knows what a proper kick should look like. And he was an actual school teacher for ~50 years, so he's very good at ...
Switch instructors. Unless this instructor is like... an Olympic level coach with decades of experience and you really love the sport, just go look for other instructors. We had a ton of kids from Korea switch over to here a couple years ago because there were a couple younger instructors (my coach likes to call them 21 year old hotshot who thinks they know ...
Some info from the IJF regarding what they consider appropriate bowing etiquette during matches:
RESPECT FOR THE FIGHT CEREMONY
The ceremony of the bow was formalized by the IJF Education Commission. It must be scrupulously observed.
The bows and particularly the bow to the opponent at the beginning of the fight must be respected rigorously and it is ...
It's quite easy.
Go to the open training time, be early.
Ask the trainer, sifu etc., if you may join.
They will ask back if you have some experience.
Tell them what is. They should know. Just don't brag.
As a sign of respect, take a white belt to the training.
They may offer you to wear your old black belt as a sign of respect.
Stick to white.
A very similar term is used in Capoeira, mestre, which does indeed mean "master", and is used as a sex-neutral term for the highest rank (grao mestre is sometimes bandied about for the more legendary figures, but is generally not awarded as a rank), where you are considered to be teaching your own lineage of Capoeira.