iPhone Calendar does not add subscribed Google calendars

Hi ;-)

I am using my Google Calendar on my Mac Mini to subscribe to some Google calendars of int'l sports organizations. All these events are displayed properly in my Apple Calendar, both on my Mac Mini and on my MacBook Air.

It seems impossible, however, to see these events displayed in the calendar of my iPhone.

I have followed these instructions:

https://support.google.com/calendar/answer/37188?hl=en&co=GENIE.Platform=Desktop#zippy=%2Cdelete-a-calendar-cant-be-undone

Now events I create in the Google Calendar on the smartphone also show in the iPhone Calendar. But, unfortunately, I see none of the events of the sports associations, even though I see them on my two computers.

Can anyone provide some help? Thanks!