It’s time for some math
Ok, so ever since I started playing bandori, I was always confused about the gacha rates in bandori, but I finally understand! Ok, so according to regular drop rates, there is a 3% of getting a 4* in a solo pull or for any given pull during a ten play. Then I thought: wait then how do people even get 4* if they expect to get one 3% of the time? So basically, the chance of getting a 4* in a 10 play (at least one 4* over the course of 10 pulls) is about 26%. So, if you are doing 10 plays, you can expect to obtain a 4* one out of every four times.
Now: dreamfest. We know that the 4* drop rate doubles during a dreamfest, so this equivocates to about a 60% chance! So you should expect to obtain at least one 4* after two 10 plays.
I really hope this helps in your bandori decisions! Stay fleeting!