First, very smooth non-absorbent/non-porous materials are just really difficult to "glue" together, then stand up to much stress.
E6000 is reasonably strong, and a thick flexible-drying silicone-type glue, but should be used with reasonable ventilation (it's not *horrible* though), and you'll get the best bond if following their application instructions exactly.
"Gorilla" is a company, and the company puts out various glues, from their original "Gorilla Glue" (which swells while curing and is very strong) to it's version of cyanoacrylate glue (instant glue) which they've named "Gorilla Super Glue", and some others (...there are many other companies/etc that put out cyanoacrylate glues too btw, like Krazy Glue, Super Glue, Loctite, Zap-a-Gap, etc. Some CA glues also have "gap-filling" abilities but not very large gaps.
CA glues are best for pulling-apart stress too rather than the more common from-the-side stress. Most glues will be okay if there isn't much later stress.
There are also certain glues that are especially strong for their type like Weldbond, etc. And the longer-setting epoxy glues (e.g., 30-min rather than 5 min) are strong too, but won't be flexible if that's needed.
Some special glues will partly "melt" plastics together for adhesion, but probably not for metal or glass although some tube glues do say they'll "work" for metal, glass, plastic, etc.
It can be best when trying to glue together very-smooth materials to use mechanical holds rather than adhesive holds alone. That means the glue can "go mostly around" a dimensional area or go down into depressions or go around projections sticking out of the surface, etc, so they have something to grab onto and *hold onto*. So even hot glue or E6000, etc., can create a mechanical hold on certain surfaces, but that seldom happens with instant glues.