While I try to change header titles by passing array of titles to options like below it does not override the headers. Instead it writes new headers first and original data with old headers again from next cell.

I am experiencing the same problem.

In addition, sheets js is mutating the header array passed in, which is not something I would ever expect.

Example:

const head

It may be a specific request but since there is a zip file handler for Android, doesn't hurt to ask for a desktop (maybe multiple backends?) implementation.

I would like to try that in the future but if anyone has time before feel free to do it.

Similar

Not a single form field has a label. These designs are not usable and the patterns presented should be discouraged.

I suggest adding a validation check like Nu Validator, aXe, lighthouse, etc. to show all the places this markup is invalid.