Most IDEs support automatic code formatting, and doing so on save. Or have it as a github hook.

At least in the future copilot could navigate you to the settings in the different places 😅

Maybe they see OP as the best candidate for an audit or code review, who has good enough skills, has time available, and is an internal resource

Not required. Looks like Java, just use reflection.

Can you give some examples of other tools for the job you'd rather use, which can be self hosted?

Keeping the clean version around seems dangerous advice.

You know it won't get maintained if there are changes / fixes. So by the time someone may needs to rewrite the part, or application many years later (think migration to different language) it will be more confusing than helping.

What does make out do?

Automatic code formatter with company style rules for more consistency across all developers.

Make those changes in an own commit, or keep it to files you already have to touch.

Since the source is XML XSLT may work to transform it.

If it's a microservice architecture using something like openapi and code generators could be a solution. Then the proper classes / types are created during the build step.

Does not avoid the fields being unused, or service B using an older version before being rebuild.

The approach would be similar as a library, but works across different languages while changing the definition only on one place.