pcbuildingadv

Im looking for something that I can game on but also everyday use . my Budget is £2000/£2500 (if needed!). My first build, hoping it'll last a little while. Mid gaming, not heavy such as Halo infinite or Forza horizon 5. Screen, mouse and keyboard I've got so I won't list it below - let me know...

So I am getting a AMD Ryzen 7 3800X a GeForce RTX 3090, 4 8GB sticks of ram . I have 450 USD to spend and I need a PC case, motherboard and cooling system and power supply. What should I get for those?