WifiManager and WiFi functionally I’m considering using wifiManager mostly to have the ability not to hard code WiFi creditntials. 
But In my current code I use WiFi’s functions as WiFi.setAutoReconnect(true) and WiFi.status() != WL_CONNECTED

How can it be done using WifiManager?
You don't. WifiManager does all that for you. You don't need anything like that in your code. Just follow the examples and read the documentation.

But if you do want to then you just need to remember that WifiManager is merely a library that configures the WiFi for you. If you want to query or alter the WiFi settings you can - exactly as you are right now. The two aren't mutually exclusive.