Dude, you actually need to pick one or the other. Otherwise you're doing a lot of picking and choosing without understanding Google Photos or you should learn a couple small suggestions.
If you can explain a normal use case example of of how you're often doing something where this causes an issue I may can offer better advice but here ya go to start:
Basically, Google Photos automatically wants to perform a local backup to the cloud of the Android AOSP default defined folder that all camera photos should be placed in.
(The DCIM folder).
If you store any pictures or video in other folders on your phone, those are not backed up unless you tell Google Photos to also back up that folder.
I personally never turn on backup for any folders in Google Photos, so the only thing it does by default is my photos taken by my camera.
If I have a photo that I took yesterday evening and I think, I should delete that off of my phone… I don’t even think twice about the fact that I open Google Photos to look at any picture I ever take. Because it is a backed up service, deleting from the delete button in Google photos will eliminate the photo from my account and put it in the trash, it will also delete the local file if I have not yet removed the files from my phone.
This is how cloud backup works for all photo services, whether it is Microsoft OneDrive on a Windows computer or anything else. There is a warning always given to a user first so that they know whether or not a local or cloud version of a file is also going to permanently delete the local version as well. Or what not
The reason I’m telling you, this is if you took a photo and Google Photos is regularly backing everything up, you should be using Google photos, as if deleting it from the cloud is deleting it permanently. Try not to think of having a local and a cloud version of the file with the way this works.
Instead, think: “If I delete this file, I have deleted it. I don’t differentiate whether it is backed up or not general cases.”
This is annoying to me on iPhone because Apple has a different way of handling the difference between files and photos as two separate file systems that you have to pick one or the other and the photos when can only be handled through the Apple photo system.
Anyway, if you have a photo that you want to keep on your local device, but you do not want it backed up to Google photos, first of all is it from your camera? Then you are going to have to make an effort to move that photo out of your DCM/Camera folder that all pictures and videos are by default inside.
This is just the way that android is organized from the system level so that everything can work together smoothly.
I use Google to access every photo I ever take, so if I think to myself, I wanted to show you right now in this post a photo I took yesterday I would quickly go open Google photos and make sure it is saved to my device and then attach it to this.
Since Samsung offers a good gallery app that is not Google photos, it often makes users confused on why deleting the photo from Google photos also will eliminated it from the device after it had been backed up.
Any cloud storage system sinking is going to do that, but it’s not obvious to many people by default that even though it’s a very simple system that it is easy to work with it’s confusing for some reason it just never explained to you. That was the default or something.
Anyway, I don’t know if this answer to your question but if you can describe what you are doing as an example of why you have a photo in photos that you also are upset that it is gone from your device, I can tell you the easiest way to not have that situation.
Just so you know, every cloud system works this way to some degree. Apple has the most obnoxious of them, since iCloud is not a backup service and instead is a syncing service. So all of your Apple devices sync, a photo, so opening an apple official photos app and deleting a picture that you took yesterday. Will delete it from the actual iCloud itself because it’s not a storage system. It is sinking in the cloud to your iPhone and your iPad too.
Still a lot of people being so confused when they computer, delete a photo they didn’t like from yesterday off of their computer and then when they open their iPad later, they think I needed that photo on here but not on my computer where in the world did it go?
Google photos is fantastic and the best way to use. It is always defaulting to using it as thinking of where every picture you ever take is going to be located, which I understand if you’re trying to move a photo out of your cloud back up then you will have to make an adjustment, but I’ll offer some advice on that if you tell exactly why.
Sorry, I wrote so much, but had some coffee and was thinking too much about when I was new to Google photos because I didn’t fully understand it, especially as a Samsung user, but once I changed my way of thinking and using it as the only default way to open a photo it made it easier to not ever even consider the problem you’re running into right now I think. Anyway, hope that helps and please reply and I’ll clarify further to help you in a much shorter post