Extend Nextcloud "User Fields" or Mange them with External Pages

Hello everybody,

I hope to find nextcloudprofis with you.
for one application, it would be necessary to expand the userfields (settings) stored at the nextcloud user by two additional individual fields. Unfortunately I did not find anything that would work after an update. An alternative would be to manage the two fields using the “external pages” app. However, for safety reasons I would like to access the session cookies of nextcloud, especially because at this external side the nc_group would be needed as a session variable. does anyone have an idea to implement that ??

thank you and best regards