"Markwatiz"... has anyone heard of this place?

I think it could be Markwartitz, a Czech equivalent is Markvartice. It could be a district Český Krumlov or Jičín.

You can use a list of German names for Czech villages.

Options for Markvartice

https://mapy.cz/zakladni?x=15.0612946&y=49.5653258&z=7&...

Yes, but written form Markwartiz is similar only of two of them. Other Markvartice have a different German equivalent. It depends on surname, religion and year of birth, then you can find more.

ok thank you everyone :)

There is 6 places of name "Markvartice" in Czech Republic - viz Wikipedia - Czech variant. There is very similar name village "Markvartovice" in Czech Republic in region of city Opava - in past Österreichische Reich named "Troppau".