so, first. What is push_amt in LND?
Why I wanna use it in with another nodes? Whats use cases?
It lets you immediately pay the other party when you create the channel instead of creating the channel and then updating the commitment immediately afterwards to pay the other person.
And some global question, how to build biggest LN Node? Just fund it with some bitcoins and open channel to every big node?
You would have to open as many channels as possible with every other node on the network. Autopilot won't do this for you.
Or, I can just run Node with Autopilot and wait?
Already waiting more than week, and here is statistics: Active channels 6
Autopilot does not just open as many channels as possible. It isn't designed for that. Autopilot will not magically make you the biggest node on the network, nor will it open tens or even hundreds of channels for you.
How to open 100 channels? 1000?
Use the channel opening commands and open then manually.