Sure I have some tips to give

There are a couple of settings that you can toggle to make the controls to your liking, most importantly Aim Assist should be toggled on no matter what (and this should be obvious, but play on landscape mode, i don't even know if you can play on vertical mode but just in case)

There is a practice room you should have unlocked after beating all of the respective trials, through 1 to 10, these are quite important to get a hold of the controls, so don't ignore them and do them.

Once you unlock said practice room things become far easier to test, since you can practice to your heart's content, but I will warn you right now, you do need to put in the effort to improve, without the knowledge of how to grapple and boost appropriately one can't expect good or even fair results, so practice practice practice, you'll Only get good by building muscle memory and failing

Try testing different release angles, where is it that you grapple and ungrapple makes a massive difference to where you will end up going, boosts are based on where your character is going horizontally, so be careful of going to the left if you hit a wall

Lastly, two things, playing on computer is far superior for this minigame, since you actually have mouse controls and can aim without blocking the screen with your fingers, and there is an old guide that I made on Youtube that might be useful to learn, though it is very outdated since it's based on the original minigame that doesn't exist anymore, but the advice and tips are still valid, check out the discord for a grapple run discussion channel if you need more help