Deleting Google Photos from Apple iCloud account without Apple Photo on device loss.

I know this subject has arisen before but I am stuck and hoping for some additional guidance.

My Photos and Photos Storage choice has been Apple going all the way back to Aperture. I have on occasions received invitations to others Google Albums and have reviewed them and that was the end of it.

Until recently I did not know that Google Photos was backing up all of my Apple Photos.

I do not like Google and rarely use it other than search or email.

Yesterday upon finding I had a copy of my Apple photos I began the process of trying to delete the Google photos.

It appears fairly straightforward using the desktop but when going onto our iPhones / 14 and 15 Promax 17.5 and try to delete a photo/s I get a popup from Google notifying me that the photo (both the Google and the Apple) will be deleted from all devices effectively wiping my photo away.

I did find in Google settings the access options and it was set to full access. I did not however understand it was backing up my photos but acting as a viewer only or to access Photos to make Google Albums (which I don't) . I have tried changing the Google Photos access limits to Limited or None but that locks me out of being able to delete anything from Google. One last item. Why can't Google Background Refresh be disabled on iPhones even when Background Refresh completely disabled. Am I missing a hidden setting. I cannot find any information on this.

Many Thanks from a 73 y/o with brain drain.