Right now id say, if you are f2p, the best path is phoenix -> geos -> imperial troopers -> Malevolence -> EP + Vader -> Finalizer -> SLKR -> Executor
now what this does, is it gives you a strong fleet fairly early with the geos, that you transition into a malevolence fleet as soon as you can, so you get as much crystals from fleet arena as possible. Troopers will knock out 2 assault battles at ct3 fairly easily, so they generate you alot of income of gear and relic mats as well.
And then you have to start worrying about executors in your fleet shard from the whales, so getting finalizer and by that SLKR should still allow you to climb in fleet arena for a while. And once you are done with the SLKR journey, you should be in a position to gain r8 materials by finding a CPit guild, and you can work on your own Executor. After that, 2nd GL and focus on teams that do well in conquest.
Things id avoid like hell early:
CLS (but once you are getting close to 3m gp, he starts to become very attractive, as he is insane in conquest)
LV (just waaaaay too expensive)
SEE (Even if you build troopers and EP + Vader, SEE has too many garbage requirements, and his value is fairly diminished now with squad arena not giving you crystals)
DR and Malak (costs too much gear and the payoff is bad, especially couse you cant rly get Malgus below 4m gp)