Combination

Is it possible to combine Local Server and Blynk Server ?
For example the Blynk server is only for Monitoring purpose if there’s an internet connection via Wi-Fi( can Access everywhere) while the Local server is for automation system( no internet connection needed)

I think it’s not (at least with common technique). Let’ s say you create a project on your local server account. It gets its own unique Auth Token.
The only way to “transfer” your project to Blynk Server, would be by cloning. But then the new project has a different unique Auth Token.
Plus the fact you should change Server info in your hardware device automatically, depending on Internet Access or not.
Of course nothing’s impossible depending on imagination as well as programming skils.
The easiest way to go is to use Local Server and open required ports on your router (8080, 9443 etc). If your router has Access to the internet, you should communicate from everywhere. If not, communication is still possible into your local network range.