If I were building a budget but competant gaming system right now:
CPU - Ryzen 5 7500F - £115
MOBO - B650 Motherboard - £125
RAM - 32Gb DDR5 6400 - £90
GPU - RX 6800 / 6800 XT / 6900 XT / 6950 XT / RX 7800 XT
STORAGE - 2Tb NVME - £90
Case / PSU / Cooler are all personal preference, but Antec or Fractal Design would be my choice for the case (Fractal North is beautiful and practical), Corsair 4000D Airflow is still good, Antec has some great affordable new additions). PSU - Seasonic / Cooler - Thermalright
I'm suggesting AMD cards as Call of Duty tends to perform better on them, and they all have 16Gb vRAM compared to the 3080's 10Gb. I would suggest 12Gb as a minimum these days.