A new GM

I am just getting into lancer and into GMing. I and my players come from 5e, so my experience is very different. I have a few questions that I want to ask to potentially better the campaign.

1. How narrative should I get? I figure this is a discussion with the players, the system itself I see lends itself to mostly combat

2. I feel like the campaign I have “planned” and how the game is it feels very structured. I’m trying to break out of it so I don’t feel too railroads but how much is too much or too little? Like plan general plot points or “cannon events” and the rest just players choose what missions etc

3. What level do most campaigns end?

4. Do yall do arcs? Like a problem takes multiple full scale missions to solve?

Thanks in advance. I initially made a roadmap for the campaign but I don’t think that’s fully what I want and I know I probably making the mistake of trying to home brew but I just felt like it.