Your information is too recent for genealogy. url https://stadsarchief.amsterdam.nl/archieven/archiefbank/inde... gives 22 families Frenk living in Amsterdam before 1939. url http://www.dutchjewry.org/inmemoriam/inmemoriam.htm list gives more then 60 jewish people that were murdered during WWII by the Nazi's in concentration camps.
url http://www.meertens.knaw.nl/nfd/detail_naam.php?naam=Frenk shows that in 1947 we had 104 people in the Netherlands with the familyname Frenk. So yes, Frenk is partly a jewish name, but not all Frenk people are jewish.
The 1950 phonebook on http://de-wit.net/bronnen/tel1950/ lists 1 H Frenk in Amsterdam. Few people had phones in 1950.
www.familenaam.nl gives the speading of familynames in 1993. There were 34 Frenk people in the phonebook, mostly in the Rotterdam area.
url http://www.genlias.nl/en/page0.jsp is the main genealogy site, but has marriages till 1923 and some later data about deathes and some early birthes. It has 475 hits on Frenk. Johann is 1 time mentioned, but there are a number of Johanne. Andries is mentioned 11 times. I find 2 times Andries Johannes Frenk, but around 1850 in Zeeland