There are plenty of foreign companies listed on American stock exchanges using “American Depository Receipts”: for example the 100 billion dollar German company SAP is listed as an ADR on the NYSE (although not NASDAQ, sorry) https://www.wsj.com/market-data/quotes/SAP
There is a list of 460 foreign companies cross listed on US stock exchanges, and that list includes a handful of german companies, although somewhere else said that there are 21 German companies listed using ADR, so perhaps the list is incomplete? https://stockmarketmba.com/listofadrs.php
Have you never heard of foreign investment? People bringing their capital, but also their skills and knowledge? Despite scare-mongering about immigrants, it's often a really great thing that we should encourage.
There is a list of 460 foreign companies cross listed on US stock exchanges, and that list includes a handful of german companies, although somewhere else said that there are 21 German companies listed using ADR, so perhaps the list is incomplete? https://stockmarketmba.com/listofadrs.php