Wireguard uses pre-shared keys, which are manually (or through some separate program) configured on each end, so one could in theory make "oh, and by the way we

Wireguard uses pre-shared keys, which are manually (or through some separate program) configured on each end, so one could in theory make "oh, and by the way we will use BLAKE3 instead of BLAKE2" part of that pre-shared key.