I'm finding that I'm pressing buttons too quickly. Is there any setting that I can change to help the game register my inputs faster, or is it something I'll just have to practice more?
I have this same issue. You just have to spend enough time in the lab to break the behavior and get your timing down. Then you go online and have it be way off anyway
Learn proper buffing. It can help.
There's this absolute beginners guide to commando Kano. Learned buffing from that guide. This helped me a lot! Worth reading.
Other than that: make hours in the lab.