looking for wonderunit storyboarder alternatives

hello i’m wondering if there are any good alternatives to wonderunit’s storyboarder on mobile? i primarily draw on an ipad and i have storyboarder on my pc and ive been looking for an app for MONTHS that has this one specific feature they have that i desperately want - the fact that you don’t have to copy paste frames and you can just move forward in the timeline and it will automatically play the previous frame up until the time the new one is drawn. that is ALL i want from that program but i haven’t been able to find anything like that, does anyone know anything?