Hi! First time posting here

So im doing my electrical engingeering degree and wanted to have a side project during my last year.
Ive been wanting to combine two PSU units i already have into a singular one.
One is a PC PSU the other is a PSU for a laser unit.
I have experience in PCB production, drawing and schematics. But i cant get a good wrap around power electronics.
So i want to design circuitry wich takes AC 230V mains and turns it into three DC outputs.
Output 1: 19.5V, ~9A
Output 2: 12V, 8A
Output 3: 4.5V, 15A
The power has to travel accross a 20m powercable and is connected to the main network.
Does anyone have any tips to get me started?
Any pointers? (Buck, flyback? / wich chips? / How do i get the right transformers?)
Ive been searching many different websites and programs but all seem to be obsolete.