The function that updates the spreadsheet will not work unless the data is structured correctly so you will have to do it in JavaScript. You have a few options here…
You will have to take some time to learn how to work with multidimensional JSON in JavaScript. This is not Wix/Velo specific so you can use any source you like.
The data you have returning has what you really want to send a few levels down so you will need to start with one variable extraction at a time something like this…
const email = jsonPayload.message[0].inputValues[0].value
(please note this is untested pseudocode, i don’t know if it will work exactly but I’m trying to demonstrate conceptually how to drill down to the data you need)
You can also just try sending jsonPayload.message[0] but that is still an array of objects so I’m not sure the function will accept that as the docs show it wants a simple array
Or if you were not hoping to learn this much Javascript that’s totally okay and you can visit the marketplace to hire a developer if you like.