You are correct. I make a distinction between spiritual systems and religions. This could potentially apply to elements of any religion that can be extracted and used as a methodology for understanding how we visualize ourselves and others in the context of the universe we inhabit. The ability to do that is controlled by how dependent that religion is on mythology as literally true to have any meaning. If the entire focus is on a mythological being to mediate the relationship of beings and things in the physical universe its a religion. Buddhism is a religion for most people who accept some aspect of the Buddha or bodhisattva as that mediator or force. But the knowledge system does not require that and at some point you discover that all beings, supernatural, alien, or otherwise must come to understand the illusion of self. This has, I think, made compassion, mindfulness and empathy the center of personal spirituality particularly among millennials with little or no connection to Buddhism as a religion.