Rust Restore / Preventative Treatment

OCD collective

Advice please -

1) What's the best metal treatment for rust? There seems to be loads on the market and need to know what is best recommendation.

2) Once Treated what is your recommendations for preventing it from returning? Is Zinc spray paint any good?

3) Paint for Chassis parts - Which paint is best for black chassis parts (front beam etc)

Let me know what you have used and what works?

Steve