I can't tell if you're trying to make a joke or make a serious point. If you want to believe you're a brain in a vat, that's your choice.

If in practice you accept that other people exist, then you should also recognize that their experiences are probably going to be different from your own.

But notice you are the ultimate authority to yourself on what is real. And I would posit to you that if you do enough self-inquiry you will find that reality is not physical, and that this is an absolute truth that is true regardless of the circumstance or perspective. The question becomes, have you become directly conscious of this? I don't believe brains in vats, all beliefs are false.