Any way to Share an App outside of Domain? Any Workarounds?

Hi, I created an Expense tracker app for my girlfriend and I. I have a Google Workspace account with a single user, Me I have a .ORG domain and she just has a standard Gmail. Was wondering if there is any way for her to use the app without me having to purchase another user license in my Workspace?

I was also thinking I could select these options below and make the app public but as soon as I save, it just defaults back to “require user signin?” as selected.