Help with moving past solipsism
My guess is you need to expand your Self to the surface of your being, your skin. Note the following argument which you presented:
Solipsistic Fact: Unless you literally internally experience of an external agent, such as random voices or God (in which case, you should connect with a therapist or pastor quickly!), you, like me and other “normal” “humans”, receive 100% of their information only from their own sensory inputs. Therefore, everything experiential is part of an internally simulated model of externality set forth by and from the brain/mind.
It assumes that you are a mind or brain, experiencing the outputs of your senses, which is contrary to fact. You are also your senses, muscles, skeleton, skin, etc. and there is nothing between you and the rest of the world. See “the homunculus fallacy” and the “Cartesian theater” for what is problematic about the argument.
I would suggest going out and being a thing for a while. Go bump around with other things, do what things do, and so on.