If you are looking for increased skill and professional credibility as a piano teacher, but do not have the time and finances to go to a music conservatory, you could consider that RCM and ABRSM both give exams - it could be useful for you to study those exams and pass them until you have completed the system. That is not nothing - it send out the message that you have mastered those levels of skill.

Additionally, if you could study with someone of some distinction in your area that would also give you an additional perspective on playing and teaching, and that also can be put on your professional resumé.

That project may take a few years, but those years will come and go anyway so at least you will have something definite to show for it - and that is permanent and something you can build upon further.

Not all great pianists and great teachers went to outstanding conservatories - you can build up other credentials if you are persistent.