How do I unlink Google Photos from IPhone Apple Photos so pictures stop getting duplicated ?

Question

I used to use Android but now I use an iPhone 11.  Long time ago, someone must've linked my Google and Apple Photo accounts. Now I have a big problem. All the photos I take are duplicated (or tripled) in Google Photos.  If I delete a photo from Apple, it DOES NOT get automatically deleted from Google. However if I delete a photo from Google Photos, it automatically deletes it from Apple.  I need to unlink them and nothing I do has worked. It doesn't look like it's set up t h st way on iphone settings.  This linkage must have been created by a Google rep over a decade ago before I had an iPhone (but had a mac).  It's not only making it impossible to manage my photos, but more importantly it's filled up my Google storage so I can no longer use my Google /Gmail account that I've had forever.