I have a question about iron guard and house of dice and smoke. I wish to learn the techniques of both sects if there are different ones, i'm currently in iron watch guard but i don't know if i'll lose my reputation from the sect and/or if i can't join it again after i finish learning their techniques and resign
Yes, the game is quite forgiving. You can resign and rejoin sects to learn martial arts from both of them, though there will be some reputation penalties.
Alternatively, you can just choose to stay in your current sect and keep wandering. Whenever you spar with other martial artists, there is a chance for their skill scrolls to drop. Basically, you can learn almost anything just by wandering the martial world for a long time!