Chosen Solution
Both monitors are from the same family and one is just a smaller version of the other. At a quick glance the mainboards looks almost the same, so could I use the, cheaper, one from the 25um58-p in my broken 29um58-p? I’m guessing there is something that I don’t know about or haven’t coincided that makes this answer a no, but I’d rather ask first before potentially tossing money towards a more expensive part.
@herorareheart looking at the connectors etc. they appear to be identical. Of course there are no schematics available for either board. Why would there be since companies are not interested in us repairing our own devices :-( If this were my monitor I would go ahead and at least give it a try. Just purchase it in a way that ensures you can return it in case it should not work.