I think you are pretty close in your assessment. I suspect they are inter dimensional and from the beginning times. Our space brother’s will appear to save us, tell us they created us and are here to help and it will be a lie. If those who claim they have been abducted by these entities stories are true then they are quit unethical and treat us as cattle, not brothers.
So, it is totally impossible that God created a big Universe and populated it? Why would this little backwater place called Earth be so special? We aren’t even in the center of things.
Could very well be part of the Strong Delusion