Hi! Welcome to the samsung members community!
Me and my gf are in the same circumstances. Should be able to on google calender and share as normal.
For some reason it didnt let us on our phones app but needed to be done on the WEB version. Once created worked on app as normal, just didnt work in the creating part
Create & share a group calendar - Google Workspace Admin Help
https://share.google/3vbWAGfngZBH3rex3*id reach out to apple if specifically want to use ios calendar