Adding as a comment since I cannot edit the question anymore:
I've just tested compiling the main application with all Hardened Runtime - Runtime Exceptions and still get the same error:
"openvpn" must be rebuilt with support for the Hardened Runtime.
Lecksfrawen
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Last seen
User for
From
Mexico City, Mexico