CPU Cooler: be quiet! Pure Rock 2 ($49.99 @ Amazon)
Motherboard: MSI B550-A PRO ($133.97 @ Amazon)
Case: Phanteks Eclipse P360A ($89.99 @ Amazon)
Power Supply: MSI MPG A-GF 750 W 80+ Gold ($99.99 @ Amazon)
Case Fans: 2x Phanteks PH-F120SK ($13.99 each @ Amazon)
Avoid AMD cards for the time being, they're a fair margin behind Nvidia this generation. They're playing catch-up, and don't pack the same suite of features. The 5600 is faster than the 12400 by A LOT in some titles, and a 3070 should be easy enough to squeeze into the budget. That way you gain access to tools like Nvidia Broadcast; which includes RTX Voice, and fairly advanced webcam background remover. Not to mention, the first-gen hardware accelerated raytracing on AMD hardware is TERRIBLE by comparison.