Something I don't really understand well.
Do I need to make a nav server to take tx fees or is it good with portfolio as well?
I don't completely understand your question, but I think you want to stake NAV?
To stake NAV, all you need is the Core wallet and some NAVcoins. You will earn 5% per year if you leave your wallet and computer running. Another method is using a Raspberry PI to stake NAV, but that is not essential.
You don't need to set a server up, that is only meant to decentralize private payments (I THINK, correct me if im wrong).