The invention patent is being accepted. How long does it usually take the Ministry to accept it? Will it be faster to apply for a third-party agent?

Invention patents are generally not that fast. You have submitted your application and been accepted. You don't need to find an agency, but you can turn to an agency for help later if you have other problems, because the process is still troublesome. If we apply here, there will usually be professional engineers to write the claim statement, and they will help to submit the application in advance when submitting the application. Usually, if there are any problems that need to be modified when returning, the engineer will make corresponding modifications, such as different picture formats and unclear instructions. It will be much easier to find an intermediary at first, although it will cost more intermediary fees.