Does the Intel Core i7-12700K support ECC memory?

No. Intel disables ECC memory controller support on all non-Xeon and non-W-series processors. Even if the BIOS has an ECC toggle, the Core i7-12700K physically cannot use it—the RAM will boot but run in non-ECC mode. If you need ECC, get a Xeon, Intel W-series, or a Core i3-12100 instead. Don’t waste money on ECC sticks for that chip.