Thanks @IliaLazarevskii for the quick reply.
I got mail and displayName to work pretty easily as you mentioned.
Could you give me more hints on how we can access custom attributes from the user profile.
I have already searched the forum and online for this. I couldn't really get it to work in the public forms - https://community.plumsail.com/t/user-profile-custom-properites/8472.
Which way would you recommend to get to the custom user attributes?
Thanks and all the best,
Felix