I want to get more than the most possible performance out of my pi 4b. I was looking around, and I saw it was possible to get just the processing unit for the pi 4 without the rest of the pi. I looked on the web, and I found NOTHING even close to "how to add a second processor to a pi 4b". Is it even possible? If so, how would I go about it?
It would be extremely difficult if not impossible. There is no provision on the Pi 4b board for a second chip, and the hardware isn't designed to support a second chip.