what fleet to max out PvE fleet stuff (need zetas and fleet 5-hard)

I’m js thinking forward (and current kinda) and I just really have no real way of getting zetas (I get 1 every 2 days from fleet shop and that’s about it, plus about a couple random every week from guild events or wtv)

and as from what I see the main way to get zetas is fleet stuff (ability materials challenge, + hard fleet battles), not counting the couple random ones from assault battles 

and for some ppl like Shaak ti there’s no way around it as I see you just need a good fleet 

so, what fleet should I go for that can allow me to 3 star every fleet battle pretty easily and not requiring like 20 months of investment 

ty here’s prof

https://swgoh.gg/p/878878617/characters/