I've pulled 10+1 gachas 4 times. It always ended up with one 5* (6* in my second pull) and the rest are 4* and below.
And my first 10+1 got me a duplicate yandere (convallaria) which I had from my first free 5* pull.
So yeah, to people who get multiple golds / rainbows in 10+1
Just kiddin