Switzerland allowed an outlet to the international financial system for the Germans ... The Swiss, for most of the war, were more than happy to sell the Germans anything they wanted that the Swiss could provide, and not ask where the foreign currency or gold came from ...
you have illustrated their best defense!
my scenario is "Great Swiss Bank Robbery" to quickly capture the tangible assets. they had gold reserves greater than amounts captured in all the occupied countries combined (excepting France, but they didn't get those IOTL)
(Stalin and Soviets made a similar maneuver albeit they conned the Spanish out of their gold reserves for "prepaid" military hardware)
Seems the national redoubt plan did not really exist in the summer of 1940. It was developed gradually through 1940-41.
my scenario for invasion would be before/instead of(?) Poland, always stated their economy would have collapsed without gold reserves from captured countries? they could have had trifecta of Czechoslovakia, Austria, Switzerland in quick order.
The Swiss had a well developed hydroelectric industry. Did the Germans draw power from that & if so how dependant were they on it?
there was one case where the Swiss refused or delayed the expansion of hydro plant the Germans wanted? (have to find that book again) it powered an aluminium plant IIRC, so tied to aircraft production. overall my understanding the Swiss were more dependent on German coal than Germans needed Swiss electricity? it seems however another underdeveloped resource the German autarky could have exploited?