I notice that you are in Italy, so you may want to check this site in the UK out as well out as well. You have to buy a minimum of 12, but shipping may be less.
https://www.laptopscrewsdirect.com/m2-x-5mm-black-zinc-laptop-machine-screws/12-x-m2-x-5mm-laptop-screws-black-m2-12-5mm-m2x5-413
They do not mention their screws having the Nylock coating, but you could use a standard thread locker such as Loctite Threadlocker 242 (Blue), or any other medium strength removable thread locker. Don't apply too much, just a small amount in the threads is all that is needed.
Warning: DO NOT use Loctite 271 (or any other brand of permanent thread locker), or you'll never get the screw out again.
Regards,