The core of patent application is patent claim, which is very skillful to write. If you do it yourself, even if you get a certificate, you may not be able to completely protect your technology. This patent may not play a protective role in practice.
As long as they are regular patent agencies, they will not give up the company for a patent. Secondly, there is a confidentiality agreement. And they won't damage their reputation in the industry for one of your patents.
I don't know. After all, it belongs to the country and may not be revealed to you.