Looks like it just concatenates them:
The shared secret is calculated as the concatenation of the X25519 shared secret (32 bytes) and the Kyber768Draft00 shared secret (32 bytes). The resulting shared secret value is 64 bytes in length.
https://www.ietf.org/archive/id/draft-tls-westerbaan-xyber768d00-02.html>
Vizio makes twice as much profit from those ads and tracking services than the actual TVs:
https://www.theverge.com/2021/11/10/22773073/vizio-acr-advertising-inscape-data-privacy-q3-2021