No, a 5700X3D is not compatible with an A320 motherboard.
No, a 5700X3D is not compatible with an A320 motherboard.
It's unreasonable to purchase new AM4 chips given how expensive boards and CPUs are. The only notable exception is the 5700X3D, but if the VRMs aren't working, a fan issue can be fixed easily. If you're planning a board upgrade, save some money and consider switching to an AM5 model—buying an overpriced B550 won't help much when you need an upgrade later.
In Poland the board you mentioned costs about 750 zł or roughly $185, whereas the ASRock model is 520, and the AX200 will be around 600 zł or $150. Increasing my budget only makes sense, so I believe I’ll go with your advice instead of trying to negotiate further on my motherboard price.