Hi Dominik,
there's a trick to let Royal TS prompt for a credential. Select the option "Specify credential name" and put a ? character only in the name.
Btw, even with shared docs, you can configure Royal TS to pick up personal credentials, see:
https://www.royalapps.com/go/kb-all-teamsharing
Let me know if this helps.
Regards,
Stefan
Dominik Zajac