I work with the devices of bigger brands, but I am trying to focus on Apple phones and tablets. I also do onboard reparations, but still have lot to learn.
Occasionally I also repair consoles, controllers, amplifiers, speakers, and easz kitchen electronics.
It will no longer be waterproof, unless you are using the exact same quality and amount of adhesive as the original one, and you press the back glass to the phone as hard as it was before.
If not, then it is hardly waterproof.