I use my 4th finger for Backspace, not 5th (pinkie). While pinkie may seem logical at first, it is much shorter on my hand than 4th. To use 4th, I only have to move my wrist to the right. To use 5th, I have to move my whole arm toward the screen, which is a much bigger deal. Same kind of thing happens in piano fingering all the time.
The other key thing about fingering is you don't want to stretch fingers if you can avoid it. Stretched fingers cause fatigue and fingers are less flexible when stretched. Try stretching your fingers apart and moving them quickly. So when finding a fingering, you want to group notes into comfortable hand positions, play what you can in that position, then move your hand to the next position. This is commonly called grouping and surfacing if you want to do some research.
You also want to avoid playing with your wrist twisted to the far right or left. If your fingering requires a twisted wrist, the notes should probably be grouped a different way, which will also change the hand position and fingering you use.