I hate being a panther, the raw meat, pooping in the woods, all that! No, why call anything God? It's like this I think, everybody is like an onion, well if you don't like onions, then a Russian Nesting Doll. Deep down inside, we are still the babies that remember their all powerful Father ( or Mother). It's not like we remember this as we would a book, or a conversation, rather it is an emotional memory - the need to be cared for - very exploitable. So, no - you can't turn into a panther and please don't poop in the woods.

The only proof is in your own heart. I realized it many years ago. When someone tells you a story and you feel their pain, that is part of that connection to all that is. It's all connected but we are the only ones we know of capable of thinking about it to this degree. I have felt that connection to the universe forever now. It may have been my escape at one time. I think we all fall into a category a little different than most. So, my argument would be for it. We are the apex of it though because we don't only exist, we think about it. If there are others out there that think about it, we either haven't met them yet or didn't know we did.

I don't even call it god. I call it all that is. All that is, is all connected and all works together with nature and the laws of the universe. We are just the apex in the picture that can grasp some understanding of how it all works together. We are getting to the point in evolution that we are thinking more than just acting on instinct. We each start off a blank slate with inherent abilities and learn what we can to pass on to those that follow us. We are each basically that same blank slate with all our information payed forward. That's just how it works. We, as time goes on, progress as a whole, just as we always have and always will. We are all the same but it's our little differences that allow us all to grow, progress and survive. All that is will always be and we are part of it so we will always be too.

Is there anything supernatural involved? I've not been convinced that anything supernatural exists.

Definition of pantheism

1 : a doctrine that equates God with the forces and laws of the universe
2 : the worship of all gods of different creeds, cults, or peoples indifferently; also : toleration of worship of all gods (as at certain periods of the Roman empire)

Which pantheism were you on about?

[merriam-webster.com]

Is this what you were looking for?

If you think about the universe as a manifestation of a God, I think is a more comfortable position for those who realize the discrepancy between a biblical God and univers, but love the idea of the monopoly of power and energy.

First, welcome! As far as pantheism goes, I can't make an argument for it because I'm an atheist and don't believe in any gods at all.
Believe what you want to believe.