For example if an iPhone is repaired of volume button and as a result battery case was removed and fixed back, would the phone remain same quality and last as an unfixed phone?…whats your thoughts on this……that’s the glue image
I’m not one who tinkers with iPhone components and thus recommend you check out some of the repair videos from the ifixit website. They may mention the use of glues, but I can’t say for certain. They are reputable and their videos are very detailed.
Apple uses Command Adhesive strips to secure the battery. Using something like superglue to hold the battery could destroy the wireless charging coils if you ever have to remove the battery in the future.