I don't ever want to sync my files using lightroom mobile and always pause sync which has worked up until the last iteration. Now, when I switch screens between say the camera and the photo library, the syncing starts automatically which is such a pain. Please, can there just be a turn syncing off forever option? Thank you.
I notice as well, that despite my disallowing photo access as I don't want Lightroom to try and upload or import all of my phone photos which include random pictures of scabs and just record keeping, and my phone is too small to use for editing, so I just don't want any of that - the app continues to pester me for access to my other photos. If this was a person, they might understand that no means no and just stop asking.
I've completely removed Lightroom mobile and re-installed twice, as well as cleaned up all of the sync issue files and those that were uploaded on the web version, yet the surprise sync problem persists.
And, even when I have specified to not use cellular data for syncing, the app is still attempting to do so which, on a 3G connection (this is in Australia) is a nightmare and just drains the phone battery with its futile and desperate syncing attempts.
It's like having a dysfunctional relationship with someone who keeps going behind your back, tries to get into your private stuff, and won't accept no for answer.
I am eager to help, but I can't reproduce the same troubles you describe. So let me ask some questions that may help.
If you are looking at the new Device tab in Lightroom Mobile, this is simply a view your of device camera roll. These photos (and videos) are not necessarily importing into Lightroom. The only way Lightroom will automatically import photos is if you auto-import enabled in LR app settings. Please check your app Settings by tapping the 3-dots menu at the top right of the app, open the Import menu, and then disable items like Photos under the section "Auto Add From Device Photos." Turning this off will stop importing new items into Lightroom.
Once you are comfortable that Lightroom Mobile is no longer auto-importing all photos, I do recommend you re-enable full camera roll access. This will allow you to more easily select specific images to edit in the future. With auto-import disabled, photos will no longer be imported from your camera roll until you edit them from Device view, or manually import them.
It seems you did already find the nearby setting Cloud Storage & Sync, and turned off "Use cellular for sync." If the app is still syncing, then it's syncing over WiFi. How are you pausing sync? To pause all syncing (for all WiFi and cellular connections) is to tap the cloud icon at the top right, and choose "Pause syncing." When I choose "Pause syncing," my preference is remembered. I can't get this to switch back to syncing unexpectedly, despite trying various things like task switching, restarting the app, doing new imports, etc.
If you have clear steps on how sync gets unpaused for you, please write those steps here so we can help further. (If a screen recording would be easier to share, here's how to make one: https://support.apple.com/en-us/HT207935)