After reading some more on google it seems like i can pass the “i01” part (after the backslash) as a property called instanceName, it works in DBeaver at least.
Knime is still refusing it though, not sure if it has something to do with this post:
And after a quick question to the database expert i got a port number instead of the instance and am able to connect using this connection string:
jdbc:sqlserver://nzsqlxxxxxxxxxx.net:<portnumber for the instance, not the standard port number>;databaseName=mydatabase; integratedSecurity=true
across all drivers, also the official one!
Thanks a lot for guiding me in the right direction!