Buying a 12th gen CPU that isn’t vPro doesn’t mean it doesn’t have ME or AMT, they all have ME, vPro only means it’s AMT Enterprise eligible. I have the 12900K which has enterprise AMT support, but my motherboard is the MSI Z690 which doesn’t have the Q670 chipset need to use the AMT functions.
TPM and TXT only matters if you want to use AEM, I don’t use it and don’t know if it’s working with 12th gen.
The version I use of coreboot doesn’t currently support memory encryption, so I don’t know if it works with Qubes.