I've been making a program in python that is intended to have each user be able to use it to access a single google sheet and read and update data on it only in the allowed ways, so ive used google api on the google developer console and managed to get test accounts reading the information that ive manually put in, however the update function returns

<HttpError 403 when requesting

Your code apears to only request 'https://www.googleapis.com/auth/spreadsheets.readonly' read only access is not going to let you write to the file. You need to request the proper scope.