“Are myopia glasses safe?”

YES, glasses for myopia are totally safe, always. You have myopia because what you are looking at in the distance is blurry because things are focusing in front of your retina (the film of your eye-camera). Lenses will refocus what you are looking at onto the retina so that things should be clear. Things will be clear for a period of time, possibly years until a prescription change may be needed. This is normal for the eyes to change and will depend upon your amount of myopia, general health, medications you are taking, and your age.
Concerning eye glass lenses, lenses that are made of a specific plastic called polycarbonate are impact-resistant. They can scratch but should never shatter.
Transition lenses will provide you with some sun protection where the lenses change color to grey or brown providing you with comfort and protection. And do not forget sunglasses if you spend time outside as the weather gets warmer. UV rays can affect the eyes as well as the skin surrounding our eyes.
Eye glass frames can bend or break unless you specifically order an impact-resistant frame which can be required for certain risky jobs. Be sure to consult with your optician or eye doctor in order to determine what is best suited for your needs personally, professionally, and recreationally. Good luck and best wishes.

Yes they will not cause you harm

yes

Yes