If John Deere is sending a tech, you've encountered something that could never be just a simple menu button. You've found a major flaw that they need to investigate in detail. John Deere would never send a tech for routine troubleshooting/repairs. That falls on the local dealership franchises. Their employees are not John Deere employees.
No, sadly not. John Deere is very anti right to repair, and they will do anything to make you call up an authorized tech.
There are authorized dealers who are not John Deere directly, but they are completely subservient to John Deere (they have to be otherwise they will not get access to the software tooling required to fix equipment), the semantic difference to a farmer is inconsequential, you will be overcharged[1] and scalped because the consequences of not paying is a multi-million-dollar heap of scrap because you cannot fix it yourself.
There are no independent tools to work on this equipment because selling a license to a 3rd party software would be in breach 1201 of the DMCA
[1]: https://apnews.com/article/john-deere-repair-lawsuit-settlem... [2]: https://apnews.com/article/deere-farm-repair-tractors-monopo...