Yoga definitely falls into the YMYL category because it is part of a person's overall "wellness."
But with that said, maybe the reason you're having a tough time ranking, even though you have 90 articles already, may have something to do with niche targeting.
As you probably already know, yoga is a very competitive niche.
It seems that everybody and his dog has an idea for a yoga blog or a YouTube channel, and people seem to be pounding hard on this niche.
The key is to come up with a way to differentiate your brand from the million other yoga blogs and resources and YouTube channels out there.
This is easier than you think.
Look for different audiences and try to cross-reference those audiences with specific regions or interests or lifestyles, and you should be able to come up with something that is uniquely yours.
Now the key is to tailor your long-tail keyword targets to specifically address your sub-niche.
The strategy is to gain domain authority, targeting a sub-niche, and then once a large chunk of your published articles are ranking, then branch out to more competitive keywords in the larger yoga niche.