honestly mashing up a lot of pre-made scripts is a totally acceptable workflow for games! i always think of it like cooking--you don't have to grow your carrots to cook them in a dish, but it might be helpful to understand more about them. when you use scripts it can be ok to throw them in and tweak them to your needs--but going into them can help you understand how they work and even replicate them in the future. exploring making these systems on your own though is a really great thing to do!
also i love your sketches aa they're so lovely!