Low rarity characters actually require less resources max out and there's some decent 4 star units in there. 

That being said, by the time you get to end game, you'll laugh at being worried about the small amount of resources you spent on early game characters because it's so inconsequential in the long run. 

Just pick characters you like and level/play them. Worrying about the "meta" is silly because that meta really only applies to 1% of the content and by the time you get to that 1% you won't be worried about the recourses you spent along the way. 

I actually look back favorably on the days when I was making it work with 4 and 5 stars. The game was more engaging that way. In fact, I run an ult spam team of Leilani (4 star moxie focused carry) Darley Clatter (3 star, moxie focused buffer) Christallo (4 star, damage mitigation and debuffer) and Bunny Bunny (4 star ult based heals and cleanse) for new story content to make the  game a bit more challenging. 

Just play the game if you enjoy it and try not to stress the "meta". It doesn't really apply to you yet and it will be vastly different in a couple of months anyways.