need help with scaling for different phone resolutions

the game has been made with the resolution 1920 by 1080 in mind. how do i make it so that what the camera sees will scale depending on resolution.

let me clarify a bit more. this is what it looks like in 1920 by 1080 Screenshot by Lightshot

this is what it looks like in 2960 by 1440 Screenshot by Lightshot

how do i make it so that no matter what resolution a phone has, what is shown in 1920 by 1080 is shown upscaled or downscaled.

thanks in advance and sorry for my awful english.

before anyone suggests a canvas scalar, it has already been done and this is not a ui problem…