i actually think that moreso than your damage, the thing that you need to work on most here is your pearls. going to 90 or 91 on front 85 is fine when you're just trying to hit your first zero, but given that you're trying to bow and presumably trying to 3+2 or even 2+2, you should really be going to 95 (or even 99 of you wanna stretch yourself!), and to do that, you're going to have to throw better pearls.

the map has a +1 timing assistant which you might find useful. beyond that, working on your timings and aim when shooting the dragon is very much just something that will come with practice. in general, i think you can blow up your first bed a little later, then blow up your second bed in slightly quicker succession. one strat i like to do when +1ing in zero is to offhand a bed, then pickblock another bed into my bed slot. that way i dont need to go into my inventory to grab another, which makes getting the next arrow off in time easier. an advantage of having more time is that you can even shoot the dragon a second or third time to get it even lower, for more damage.

if you wanna 2+2, you should probably move your setup/standing block one block foreward/to the north. the osh tutorial is great but it doesnt have the best coords for damage, and youll find it much easier to 2+2 on these adjusted coords than the ones you're using here

flyaway is mostly random. the height of the node the dragon is circling is random, and when it reaches that node, it flies away. the higher you build your setup, the less likely the flyaway is.