It appears the M50 II is the exact same hardware with a firmware upgrade. Would it be possible to imagine the firmware off of a M50 II and then load it on the M50?
No.
Even if they had the exact same hardware, flashing the firmware from a different camera model would be copyright infringement.
https://www.iprhelpdesk.eu/news/copyright-or-patent-how-protect-my-software
Following the aforementioned, copyright will protect only the computer program in the form written by a programmer i.e. its source code. Neither the functionality of a computer program, nor the programming language nor the format of data files used in a computer program in order to exploit certain of its functions constitute a form of expression of that program, and thus these are not protected by copyright.
Have you read your quote and understood it fully? It's still applicable to binary (compiled) form of that program.
Also, assumption that EU law works around the world...