Did you try disabling TPM 2.0 in BIOS?
Disable TPM 2.0 -> Windows 11 doesn't meet minimal requirements -> Windows 11 can't be installed.
As for me, I did not enable TPM 2.0 in BIOS at all. This is why (I guess) I never got Windows 11 downloaded automatically. Also I've disabled the whole Updates Centre via gpedit.msc later, but that seems to be more than enough for what you're trying to do.