may i bring this up again, as i am currently trying to solve a similar issue.
I read through the discussion in Setting default user role on creating in panel and also followed the argumentation given in Setting default user role and language on creating in panel · Issue #347 · getkirby/ideas · GitHub which i can follow … but … what if we start dialog with the given option (which seems to the users’ own role) and then store the latest option which is preselected when another user is created?