Need A shopify Developer with knowledge of shopify liquid language

Hello i am looking for a shopify website developer. My website is almost ready and needs final uograde. I am looking someone who can:- (mobile + desktop responsiveness)
1. Optimise the website
2. Optimise the speed of website
3. Impove UI/UX of website
4. Optimise apps and functions
5. Take customer to checkout page with less hassle

I need a complete professional person having experience in shopify and knowd in and out.