Consumer Intel CPUs don't support ECC.

No. Even if the BIOS has an ECC toggle, the Core i7-12700K physically cannot use it.

ECC requires memory controller support built into the CPU. Intel intentionally disables that on all non-Xeon and non-W-series processors. The RAM might boot, but it will run in non-ECC mode—the error correction just won’t happen. Some motherboards let you enable ECC in BIOS, but that’s a lie; the chip won’t take the hint.

If you need ECC, you need a different CPU (like a Xeon or an Intel W-series) or a different platform entirely. A Z690 board can technically run ECC UDIMMs with a Xeon or a Core i3-12100 (oddly, Intel left ECC enabled on that one), but not the 12700K.

Don’t waste money on ECC sticks for a gaming/workstation build with that chip.