Auto sync disaster

I'm not sure I understand the issue that you are having. Specifically, what does "Accidentally hit auto upload" mean, as there is no "auto-upload" option in LR mobile. The app itself is designed around the concept that it will automatically upload every image that you add/import to it, and that cannot be changed. Yes, there is a "pause sync" option, but that's not intended to be permanently used.

Without further details, I'm just guessing.....but my guess would be that you have the option in the LR mobile settings to "Auto add photos" enabled. That means that any new images added to the native photos location on the phone (e.g. Camera Roll on an iPhone) will be automatically imported to the LR mobile app, and from there will be synced to the cloud. Now, if after installing LR mobile on the new phone, you then restored all the photos from the previous phone (by for example doing a restore from iCloud), then it is entirely possible that all those restored photos would be automatically imported into the LR mobile app, and thus will start syncing to the Adobe cloud. Is that the issue that you are experiencing?