The new chips are so powerful that most emulated apps will no longer feel emulated, which was a big hurdle for Windows on Arm to overcome.
So probably they’ve got an x86_64 emulator on board to be able to run non-native programs.
If I was prone to conspiracy theories, I’d think they plan to switch entirely to ARM and drop x86_64 support for Windows 14 in order to create a walled garden.
AFAIK, clamAV hunts Window viruses, not Linux malware. The linux equivalent I know of is rkhunter.