How well can we bring out the difference in meanings between ‘excess’ and ‘extra’ by way of suitable examples?

As I see it: put simply, ‘extra’, more often than not, sounds close to ‘bonus’; ‘excess’–close to ‘overkill’.

‘Extra’—“ to a greater extent than usual; especially: he is trying to be extra good" [bonus] – ‘Excess’ would spoil it.
a sandwich with extra mayonnaise.[bonus] --like previous.
She got a part-time job to earn some extra money[bonus]. –‘excess’ would probably deprave her.
He gave us an extra week to finish the job.[bonus]. “Excess’ would mean it was not asked for.

Excess’—“an amount of something that is more than necessary, permitted, or desirable: are you suffering from an excess of stress in your life?"
“Excess is too much of something, like big-time overindulgence.”
“An example of excess is leftover food at a dinner party. An example of excess is police force that is too strong for the situation. Sometimes you have an excess of a product and the only way to get rid of it is to have a big sale or promotion.”

Adequately exemplified. Thanks, Eugene.