Making My Own SBC PCB?

Basically, I want to design and make my own SBC PCB. However I'm not sure what parts or even how to make one. I know I want it to be able to run Linux, have relatively good graphics for Linux, but most Linux users don't use Linux for its "amazing" graphics. It would definitely have to be small ish? Like maybe a little larger than a raspberry pi, but it would need to be faster and maybe more efficient. USB type C ports, especially for power, and USB A ports for peripherals. Not sure about A V outputs, obviously not the older round ports.

Could anyone recommend anything at all?

May be interested in selling some if it all goes well.