... To this day I'm angry about Having to tighten my MacBooks screws weekly. I've taken it in, they've changed the bottom twice, no matter, screws come off weekly. That's unacceptable. ...
A fix for that is at your local hardware store. Loctite is a specific brand, but any threadlocking adhesive will work.
I'd use a tiny amount applied with a toothpick to the threads of the screw. I'd try it on one screw only and see if it worked for 2 weeks, before committing to all the screws.
Maybe I'm missing something, but how would replacing the bottom be a fix for loose screws? You'd need to replace the part the screws screw into (the chassis), not the part the screws hold on (the bottom).