Any proof of existence of anything relies on prior assumptions, the seeming least of all is that we exist such that we can observe.
There is no definitive proof of anything that is not reliant on our subjective reality.
Scientific objectivity relies on this too, it cannot exist without our subjective acceptance. Any claims that reality exists independent of us is unprovable.
Yeah and what? We don't ask for absolute proof of God, of course it's impossible to get. We ask for a logical proof based on logical assumptions...