No yaoi suggest some nice novels where the protag focuses alot on raising his disciples/underlings/servants/armies, hell even idol management is fine. has to actually be somewhat of a focus of the story though not just "hello jadeskin beauty i shall give you a good cultivation method lets meet again in 500 chapters where you will become my wife"
also Spoiler mc kind of... not a great mentor, he does sort of start a war and makes a bunch of "apprentices" fight each other to the death to refine them into a magical treasure...
If you don't mind a japanese one R(away from the hero) has a teacher protagonist i only read till chapter 60(at the time there was no more) but i thoroughly enjoyed it especially when he would make his students go through brutal training idk if i enjoyed it because i am a sadistic person or i i real liked the creativity of covering up torture as training. Nevertheless it isn't only about training but i did enjoy it fully at the time and hopefully will continue the rest(maybe when it is completed)