So it was on the list and they took it off? Or it's still on the list but they're saying it's not compatible?
Hrmm, I wonder if they're looking at the QVL for 10th gen. Your kit is only on the list for 11th gen k (which you have).
Anyway, it seems like sometimes certain BIOS versions have issues reading spd values from modules. I don't remember the thread but there was a BIOS with a bug that ASUS eventually resolved that sounded very similar to what you have experienced. Unless you have a specific reason to use 1202 I would go back to an earlier BIOS that works correctly. In the future if a new BIOS is released with patch notes about memory compatibility you could try that.
Alternatively, you could try using a RAM calculator to get values for your modules and manually input everything. That *should* work because you're not using XMP.