No patent can be protected by known technology. Before the filing date of the patent for utility model, if the first product already exists, there will be no problem of patent infringement-no matter how creative, novel and practical the patent is, no matter what the scope of its rights protection is. Unless you make an improvement on the first product, which falls within the scope of patent protection, it is infringement.
3. To judge whether the utility model is established depends on what its claim is. If you think it has not improved compared with the previous technology, you can apply to the Patent Office for invalidation.