Is there a hardwire connection that would speed up the transfer from one Mac to another?

the cases where a direct cable connection is possible are very obscure, and depends entirely on model-year of each MacBook Pro and its available interfaces.

Ethernet through your Router can be much faster than ordinary Wi-Fi.

simply stretching an Ethernet cable between them does not typically work because they have no IP address.

If both Macs are on Sierra or later Migration Assistant will set up an Ad-Hoc Wi-fi connection to do a computer-to-coamputer transfer, provided the computers are right near each other.

ThunderBolt connection is possible, but must be configured and in place before you begin, or it will not be used.

USB connection is a complete dead-end.

Depending on the individual Macs involved, you could use a direct ethernet, thunderbolt or USB connection.

However, you did not say exactly what Mac models you are using or what type of transfer you are currently using, so it's not possible to give specific advice.