There's a higher chance of drawing 3 B2B SSR than 1 pre-60/70 MiHoYo 5 🌟 (when the odds start increasing until hitting 100% over 20 rolls)
Base MiHoYo rate is .6%, 50% chance to get the banner if unacquired, guaranteed if you lost the last coin flip. Nikke is 4% for SSR and more generous with draws