The thing with the spiritual practice of yoga is that it doesn’t exist in a vacuum, but in the theoretical landscape of vedanta. And what vedanta tells us is that everything that we are and everything we perceive in any way, takes place within the mind of God, who is the only reality, the Absolute, level 0 reality.
When you realize that from a first-person experience and decide to tell others, you are a guru. When you hear about it, believe it is so and start doing something about it, you are a yogi. That’s the yogi approach to things: change yourself in order to stop being deluded by things that are not the highest reality. The reason why you don’t see God isn’t because God doesn’t exist. If you look through a microscope and don’t see the stars, it’s not because there are no stars, it’s because you’re stupid.