I think the only way the Swabian front is going to move is if I get some heavy cav on my hands. Something with high attack and charge bonus. Frankfurt is so very close to hire teutons from

There is pretty much no chance you could win against that Metz (or even the Dijon) gold stacks unless you exploit the heavy cavalry. They got triple gold fully upgraded DCK which are arguably the best heavy infantry there is that can be upgraded and retrained, making holding a bridge an impossibility when you consider they also got trebs and basilisks at triple gold with them.