Did you use DDU prior to removing the RX570 to replace it with the RTX3060? If not, that's your first problem. Reinstall your GPU drivers after using DDU in an elevated command, with the latest sourced from Nvidia's support site. The other problem is this;
Ram: 16gb 2133mhz 8x2
You'd actually see an uplift in performance from your platform by swapping the rams out for a 2x8GB DDR4-3200MHz dual channel ram kit, with tight timings.
PSU: Corsair CV 550
You have the wrong PSU for the job, as it's a VS series PSU with a different label. Even if it was brand new, I'd have suggested to replace it with something more reliable. Considering that it must've powered the RX570 for a number of years, that's a no-no.
Chassis: https://www.ebuyer.com/826971-eg-wider-x3-mid-tower-gaming-case-eg-wider-x3
I'm having issues visiting that site. Do you have the full tempered glass front panel variant or the one with the mesh with the LED fans?