Placing back the rear glass properly

I’m having trouble getting a tight fit on a rear glass replacement. Every tiny speck of glass has been removed from the back, as well as some sanding been done to flatten the overall surface as well, however I still fail to get a fit as tight as before.

I tried checking with a local shop to make sure if the glass I got wasn’t simply a badly made part, too short, thick or thin from our good and reliable Chinese sellers, but they confirmed it wasn’t the case, noting only the lack of a frame originally attached to the removed glass as the reason for the improper fit.

I don’t recall any frame besides the plastic one already attached to the chassis which was somewhat damaged, but not significantly. Any bends caused to the phone during removal were made inwards, not outwards, so I still don’t quite follow why I can’t get a good fit.

Strong pressure on the glass only gets it so snug, let alone any adhesive that is going to be used to get it stuck to the rear, so I’m worried it might end up even worser than it does when I simply place the glass on with my fingers.

Does anyone have any experience with getting the glass back on properly? Any tips?

Attached below are, perhaps not the best pictures, but exemplary enough of most of the issue throughout the frame: