well there is a fact that its RNG. I too was pissed that I wasted 100 FGems on Premium. had I waited for the "Limited" pulls with increased rates, I might have been a much happier camper right now.
Dont do premium, save up for better rate Limited pulls.

And yeh its BS, there should be some way to get better pulls without the 3* "trash" (no disrespect towards them 3*). But no game that ever based itself on "RNG character Gacha" where money was involved did this. After all they expect you to buy tons of gold FG and use them for pulls.
If it was "real money" - "Flower gems" conversion (like what Riot does with League of Legends) that would be fine, but I hate when they go for a sick greed cashgrab that is set as "real money for gold, gold for flower gems". Going through one extra game currency diminishes the value of real money by hundreds.... Was it not for this more people would actually spend their cash on the game, I guarantee
(again, look at Riot and how they managed their ingame purchase system, much better, and the customer does not have a feeling of getting scr*wed up the ass).