Please read the postings from @schaeferms95 completely, before you post any links without context.
He is asking for a driver that supports Apple Silicon, but this is not available. The device has been discontinued for some time now, the last drivers are from 2019 and support Intel Macs only.
Also, if you click on the download link in your second URL it leads to an error page, so this is again not helpful.
@schaeferms95 As I wrote in my first reply, you need to contact Yamaha Support to get a definitive answer.
But to be honest, even if you get hands on the source code, if you have never worked with stuff like that I really doubt you will get anything working out of it. It is not just compiling the code, there is much more around it.
While I cannot speak for Yamaha, I am confident that there will be no driver for any of today’s operating systems. The MR816 was discontinued years ago, and the source code won’t be released.
Additionally, bear in mind that as of macOS 26, Firewire support is no longer available on macOS.