next time Tailor's online can somebody pls remind me to ask him if he's a pantheist
I don't know about Tailor specifically, but a lot of Sufis, and mystics of various backgrounds tend to hold pantheistic views about the universe. And yes, according to Islam's teachings, it is shirk, which is why many (most, I'd say) conventional Muslims consider Sufis to be apostates or at least, heretics.
The difference, as I understand it, between pantheism and panentheism, is that pantheism requires no "worship" as there's no external diety to please/appease/pray to, while panentheism may require such worship, since panentheism states that an entity, let's call it "God" for the sake of simplification, is itself the universe but is also "beyond" the universe, therefore, in that way, panentheism is similar to theism and deism. Pantheism essentially says the universe(s) and everything in it is the totality of itself which some may call "God".