So, what would objective evidence for god/religion look like?
Ultimately, there is no such thing as objective evidence. What you most likely have in mind is inter-subjectively verified evidence. That is, evidence that is verified by two or more "subjects" or people.
Miracles might qualify for inter-subjective verifiability if either they could have been or they actually were witnessed by two or more people. So, if you and I are sitting next to each other, and we both see -- or claim to see -- a guru levitate off the ground, fly a hundred yards, and land again, then that would amount to inter-subjective verification. However, note well that one instance of inter-subjective verification alone does not preclude a later instance of inter-subjective verification that it was all done with smoke and mirrors.
Mystical experiences are a bit more problematic. If you and I are sitting next to each other and you have a mystical experience, who am I to say you have had one? On the other hand, if you describe your experience in terms that significantly match or correspond to another person's experiences, such that we can say you most likely experienced something the same or similar as that experienced by the other person, then your and their experiences are inter-subjectively verified.
However, they might not be reliably replicable. That is, it might be impossible to replicate them in any reliable manner using any known technique or means.
Last, even if you had a mystical experience of, say, "seeing deity", that would not necessarily mean you had seen an actual deity. It is possible that you have merely uncovered a relatively rare kind of brain fart. Or you might have merely seen something that bears the same relationship to deity as colors bear to the electromagnetic spectrum. That is, colors are not "real" in the sense that they are properties of electromagnetic energy, but are only "real" in the sense that they are mental interpretations of the presence of various wavelengths of electromagnetic energy.
Ideally, to provide solid inter-subjective evidence of deity, you would need to make a prediction about some event that will come about if and only if there is a deity, and which eventually does come about. Good luck finding that event!