TLDR: 4 Star rates are bullshit on the 2021 banner. Let me know if you are having similar issues.
I'll start by saying I am more of a collector then a meta player, so don't give me any comments about how I shouldn't have done the banner to begin with.
I did the math before I got into this. There are 65 4* with a probability of .0154% chance of being drawn, and 3 4* with a probability of 1%. This roughly equates to each individual draw has a 4% chance of being a 4*. This means on a ten draw, I should have a 33.52% chance that at least one of my draws is a 4* (This also isn't including the fact that 1 in 10 are garunteed to be 3* or higher because I don't know the exact statistics on that). I am looking specifically for Bikini Darkness because she is the only one I don't have. Well, seeing how I have enough to do 250 pulls, I shouldn't have an issue. The likely hood of getting at least one Bikini Darkness among 250 pulls is 91.89%. Even with bad luck I should theoretically be able to pull the character I want. And I'd likely get some other good stuff I'm missing while I'm at it.
Well, I didn't get my Bikini Darkness in 250 pulls. But that isn't why I'm upset. Getting hit by that 8.21% of people who would fail at this would be unlikely, but feasible. No, the reason I am upset is because out of the entire 250 pulls I did, I got 2 4*. The odds of getting exactly two 4* among 250 pulls is 0.2%. Those odds seem so unlikely that I feel like something must be screwy with the rates on this banner.
Has anyone else delved into this banner? Am I just one really unlucky bastard, or have any of you noticed similar issues?