issues with original header and plugin header in a particular size

https://ibb.co/PQt70ry
https://ibb.co/GP0ykPn
https://ibb.co/ZYgx38q

after 480px to approx 1100 px the header dissappears
i want phone header to be visible until desktop header starts showing !and hide it when desktop header is visible !

also when i remove display none , i am able to see old phone header , i need to know how to permanently hide or remove it as well!

The page I need help with: [log in to see the link]