Creating socket with socat

I'm trying to make a remote socket local by using socat.
The idea would be

     Remote: socket -socat-> TLS
     Local:  TLS -socat-> socket

When I run:

socat UNIX-LISTEN:remote.socket,unlink-early OPENSSL-CONNECT:remote..

on the local FreeBSD 13.2 machine, it appears to wait for connections,
but when I try to do nc -U remote.socket it fails with:

     E setsockopt(7, 41, 27, {1}, 4): Invalid argument

The remote, for their part, doesn't even register the connection.