Removing the 'shot on' watermark from my own phone photos

when you use the eraser in Google Photos, pick save as copy rather than overwriting. the edit can look fine on the phone and messy once it's printed or on a big screen, so keep the original.

Two separate jobs here. For new photos, turn it off in the camera app's settings. On Samsung it's Camera > settings gear > Watermark, on Xiaomi/Redmi it's usually called 'Shot on' watermark under the same settings. Other brands bury it in a similar spot. For the ones you already took, the watermark is baked into the image, there's no undo. Cropping is the quickest if it sits in a corner. If cropping would cut into the shot, the object eraser in Google Photos or Samsung's gallery editor does a decent job on plain backgrounds, less so over busy detail.