How does one find a GOOD coach?

TL;DR: how can I tell if someone is a good vocal coach with reasonable prices or not a good coach/overpriced

Everyone Ive spoken to and everything I’ve read has told me that a vocal coach is the best and easiest/fastest way to learn to sing. But I’m very skeptical of a lot of coaches, and for a good reason

CONTEXT PARAGRAPH!

I’m a personal trainer and bodybuilding coach, and I’d argue a very good one. I pride myself on being VERY knowledgeable and science-based. But I’ve seen firsthand the amount of personal trainers who not only charge as much as or more than me, but are also less qualified than me, who simply DONT KNOW WHAT THEYRE TALKING ABOUT. Trainers who preach bad or unoptimal practices, who don’t understand studies, and who just don’t train intelligently. And it pisses me off that people will buy into them and waste their money and time with shit coaches.

**Obviously both kinds of coaching are just that, coaching, and so I assume there’s some parallels. But unlike personal training, I have no clue how to pick out a good vocal coach from a bad or unqualified one. I’d love some tips to weed out the bad coaches, and for someone to help me find what to look for.**

If the info helps, I’m mostly into rock/grunge, and I’m a huge fan of Nirvana, STP, Alice In Chains, Soundgarden, Pearl Jam, Radiohead, and Jimi Hendrix.

I’d consider myself a very okay singer, pretty good for having no formal experience or knowledge/training but not good enough to turn heads at karaoke night.

I have little to no practical knowledge of singing and odds are I’ve PROBABLY developed a bad habit or two from shittily singing in the shower.

Help? Thanks.