>>What does Mexico have to offer Germany other than avocados and illiterate wetbacks?<<
Mexico has huge manufacturing capabilities in Monterrey and Saltillo to name just two.
They are very much a modern force to be reckoned with. Mexico actually priced itself out of much of the USA market by paying much more than Chinese labor (which as Trump has pointed out has continued).
NAFTA did NOT help the USA in that regard.
Mexico’s problem is shipping whatever it is they intend to export across the Atlantic. That will be a big expense they don’t have now.
Germany doesn’t need any high priced technical goods or services only Mexico can provide. They need cheap parts and/or assembly for their products. Cheaper than what they get now from SE Asia which is dirt cheap as you pointed out.
Whether they like it or not, Mexico needs a happy big daddy up north.