The cert doesn’t make the coach/instructor. And even though education is very important, education itself is nothing without application. Heart is even more important. And if you love what you do, you never stop learning, applying, and helping.
I tell all of my own students if you are unsure of which cert to start with, start with ACE or ACSM. Then spend time teaching what you know and sampling things that interest you. If you find something that sparks you to act, go for it. Then continue from there.
But if you don’t like what you are doing, move on as soon as possible.