It isn't expected that a quantum computer will be able to instantly break symmetric encryption, as is used in full disk encryption. It will give an enormous advantage (halving the number of bits of security) but attacking that will still require a large amount of time and energy. What a CRQC will very quickly break is the asymmetric primitives, as used in TLS, encrypted email and chats, etc.

On the other hand, using default parameters from not so long ago, it is cheaper than you might expect to brute-force your disk passphrase already today without a quantum computer... which is why you should use a stronger key derivation function (in addition to a strong passphrase, of course).