I need help building a budget PC with room for future upgrades for my AW3225QF monitor.

I'm trying to build a budget PC right now, that is also easily upgradeable, that way I can fully utilize my monitor later. So far, I'm thinking about getting a high-end case, power supply, and motherboard. Since I don't want to pick everything a part later on when I'm get a new gpu/cpu. I don't want to spend too much on gpu/cpu yet, since I just want to play some games with my friends. I'm thinking about RX 6600 with ryzen 5 7600 for now and upgrade to 40 series later on with ryzen 7 or 9. This will be my first time building a PC so, I welcome any tips, recommendations, what to do and what not to do. Thanks !