Because of that, I recommend you go for some of these targets as a side/big picture project. But, the recurring resources are going to shape how far you can go and how quickly you do that. The accessible meta characters should be a NO brainer. You have a tremendous amount of time to build your apex teams. I'm going to go a different route with my advice. From there its pretty much where you wanna go with your roster and what you want to accomplish but everything should come much easier with the flash events giving you heaps of resources. You can also use those 3 with zemo as an early arena team.

With her and sharon carter and shang chi u have the foundation of your raid team. From the war store maria hill is your top priority. Dont open raid orbs because they will bloat your roster with characters you dont need all that much(there is no taid orb exclusive chracter like shang chi in the blitz orb).

Also from the raid store u want sharon carter. From the raid store u want zemo asap he will be the backbone of your arena team for a long while. Youll get a few more characters along the way as well but none are nearly as important as him. Early on keep opening those blitz orbs eventually youll get shang chi hes a must build. Stores will be you best method of farming. Along the way youll unlock a few characters with orbs and get some decent red star pulls if some better characters that you will want to build.

Honestly i would focus on event teams, first mercs for villains campaign and skillitary/wakanda for heroes and get thru the campaigns with them they require much farming. Node farming is real slow and you cant get to chapter 7 of the campaigns or the doom campaign (where many of the best/required options are found). Since you brand new you only have so many options.

Marvel strike force 0.3.1 best tank