They can be deprecated for confidentiality purpose, but DNSSEC doesn't use confidentiality.

You're trying to argue that DNSSEC isn't exposed to HNDL attacks, so can use signature algorithms that CRQCs break. But that's neither here nor there: the approaching cryptographic research consensus is going to deprecate all ECC (and all RSA); yes, signatures aren't the priority for immediate removal, but nobody is recommending ECC signatures. The point is all this is happening just as ECC in DNSSEC may finally be stabilizing.