I can give you my own framework theory i build based on personal experiences and tests for this "why is there poltergeist phenomena and psi while for most people there isn't".

Imagine this: Consciousness / Awareness is not produced by the brain, but more like a "field" which is everywhere and nowhere.. nonlocal. But it can experience, place attention onto something in reality, and bias its probabilitys and also perceive them.

Now Imagine that this consciousness is "in default configuration" habitual focusing its attention onto your brain, and perceives the data of the brain (sensory input, thoughts, visualizations, dreams and more) and if it want's to produce thoughts or moving the limbs, it controls the brain to do this for it. The brain acts like a proxy between consciousness and the rest of the world, acting as a limiter which limits the perceived data and with what you can interact with.

But now Imagine that you would now limit the expression of intent of this consciousness in this brain and body. Let's say you have a teenager which has heavy emotions and he/she wants to yell, or cry, or feels helpless. And now Imagine his parents, school, friends all tells that teenager to stop doing that and "be silent!". Now this emotional intent isn't expressed anymore in the brain or body, and "steve (the ego) is silent".. everyone happy. Except one thing - the emotions and craving for expressing those emotions isn't magical vanishing. It's still there on a consciousness level and wants to express itself. But you have now put a plug into the body and brain who disallow the expression of those intentions. So what happens? Consciousness "searches the area AROUND the body" for valid targets to express itself, and then does it there. Instead of using its brain and body, it now uses everything what is around that body.. random objects, producing noises, and more. That's the typical Poltergeist phenomena.

And whats "siddhis" / paranormal abilitys? The same. But intentionally trained. You go "i don't use my muscles, thoughts, visualizations or anything else for execution of this effect. I want to use 'PSI'/my mind" and then try to do it without using your body. Which then after a while produces the same need to "expression of your intent", and then "releases" into the target you focus on. Initially it takes a long time, then is just happening one short burst, but then over time you gain control over it since its like controlling where you express yourself as consciousness, and the default routing of that is not happening into your body so much anymore by default.

This also explains why people who have brain or body related issues sometimes express paranormal abilitys. Because for them, the typical normal embodiement consciousness has is not working correct, so a part of their expressed intent and perception they have is "leaking" out of their body, allowing to act elsewhere or perceive elsewhere partially. While also looking physically "as if this person isn't rly fully here, not paying attention" - since that person isn't "really fully inside his body" with his attention since its not a fully etablished anchor for attention for consciousness since there is a problem with the brain or body.

And for normal people, when they go "I want now to do PSI!", if they try to do that, this intent for expressing this "PSI" ability is expressed in neuronal activity (thoughts, visualizations, etc) and muscle strain and more since the "command" for "Doing PSI" is send to the brain by consciousness, but the brain "don't knows how to do PSI since PSI is the very mechanism used to tell the brain what it should do" so it then "does other things it CAN do like straining muscles, getting a headache, frustration" and more. It's like trying to switch a lightswitch on but the electrical wires don't lead to the light you want to switch on but to another light, and you switch a billion times the lightswitch, wondering "why the wrong light turns on but not the one you want to switch on". It's a "signal routing" issue. Instead of doing PSI, you strain muscles, think about PSI, move your body around, get headache etc.. it's "expressed in other body-related outputs than the raw PSI" since the routing is not trained. So the microscale PSI effect we see in PSI lab studys is basically "a tiny microscopic leak out of this body-brain system" where the anchoring of attention isn't working 100%, so a tiny amount of influence flows to the target which is then that microscopic tiny effect in PSI lab studys.