I would ensure CP works before upgrading to 3.4, that’s why I said what I said before. CP should be working already if you have the correct build, hub and cable.
You can try installing 2.2.17011, check this post → 2016 Mustang Sync3 1.0 updated to 3.0 and no Apple Carplay! - #10 by SaNdMaN (nevermind this, I saw you are already on that build)
If with that CP does not work, make sure to use a certified cable since Android Auto is more forgiving.
Again, my recommendation is to make sure CP works before upgrading to 3.4.