Please do explain why you think that having 3 different refresh rate monitors will play well when you game on all 3 at the same time.
They will run at the slowest refresh rate, losing the advantage of the 144Hz. Also, being able to use 3 monitors for gaming is NOT the same with using 3 monitors for any other work and 1 of them for gaming. It's way more taxing to the GPU. A 2060Super MIGHT be able to handle triple 1080p@144Hz in some games with settings lowered but since CPU does play a role as well, I honestly don't know if the 3600 can keep up. I need to do some research.
EDIT:
Found this:
https://www.tweaktown.com/asktheexp...ould-consider-for-sim-racing-build/index.html
It's very similar to your system so you know what you will get more or less. It's mostly what I said above, but do take a look at it.