But it's not automatic. You gotta do it manually https://support.apple.com/guide/mac-help/ip-thunderbolt-conn....
I would have expected airdrop to automatically switch to thunderbolt if such a connection exists, but it doesn't.
1. Thunderbolt Bridge exists and is enabled.
2. All active (enabled, connected) interfaces get link-local IPv6 addresses.
3. All active interfaces without static or DHCP-assigned IPv4 addresses get link-local IPv4 addresses.
3. Multicast DNS (Bonjour) is enabled.
So basic networking should be automatic, though no file sharing services are enabled by default.
1. Thunderbolt Bridge exists and is enabled.
2. All active (enabled, connected) interfaces get link-local IPv6 addresses.
3. All active interfaces without static or DHCP-assigned IPv4 addresses get link-local IPv4 addresses.
3. Multicast DNS (Bonjour) is enabled.
So basic networking should be automatic, though no file sharing services are enabled by default.