Is patent authorization risky?

Generally speaking, an application for a patent for design and utility model can be authorized only by preliminary examination, so the risk of authorization failure is small, while an application for a patent for invention can be authorized only by preliminary examination and substantive examination, so the risk of authorization failure is large. The longest search period of this patent application is 18 months. During the confidentiality period before publication, no one can search its information through public channels.