Safely get rid of Google Photos without losing the photos in iCloud

I've read several articles from Google support and I'm still confused and fearful about what I'm trying to do. Since it involves apple devices and iCloud photos backup, I thought I'd ask here.

What I've read so far explains so much (and so well, so I applaud that -- it works for people not easily confused about tech stuff) that the Simple Cases get overly complex.

I want to disengage Google from all my photos on all my devices (iMacs, iPhones, iPads, PCs). I want to use iCloud ONLY, for photos backup/sync. The reason is that I've run out of room on my Google Drive and want to free up space. I've already downloaded all my Google Photos and imported them into the Photos App on my iMac. I assume that they are now also backed up in my iCloud account.

I currently have Google Photos on my iPhones and iPads and want to get rid of the app on all of them. One cloud backup for my photos is enough, and that's iCloud.

I want to continue using Google Drive (now Google One), but I don't want it cluttered with Photos. I have the unfortunate Backup and Sync app enabled on both my iMacs and a couple of PCs. I have them set to backup ONLY the Google Drive folders on those machines, so they can share data files the way you can with Dropbox. (Before Google "upgraded" everything, Google Drive used to function almost exactly like Dropbox, and it was less expensive, or I would have gone with an upgraded version of Dropbox and ditched Google Drive.)

So my question is: What do I have to do, step by step, in what order, so I can keep all my photos on all devices + iCloud -- but free up the 30 or so GBs on my Google One account that are currently taken up by photos.

I know you say that Google isn't spying on my iCloud, that they were born separate and remain separate. While that may be true "under the hood," it is not FUNCTIONALLY true, when dumping Google Photos actually causes deletion of iCloud photos as well!

I'm sure that there are other users who want to do something almost identical to what I have described. I can't be the only one who resents Google trying to force us to upgrade our storage by making things so complex and confusing that we're afraid to NOT upgrade lest we lose our Photos.

Can you tell me what I need to do, step-by-step, without mixing it with the details of how the various systems work? There are times I'm after the Education (most of the time, really). But here I just want to be told what is the safe thing to do to get Google Photos out of my life.

As an old aunt of mine used to say, "I need something designed by geniuses to be executed by idiots"! I implore you to share your genius with this idiot! 🙏