The post says:
reply> This is wrong, a discovery that took me about a half dozen attempts to update macOS on an external disk. I have a 16-inch MacBook Pro with an M4 chip, specifically an M4 Pro chip, and the DFU port seems to be the USB-C port on the right side of the Mac, not on the left side."
It appears that the author is directly contradicting your read.
Now the question is: what is left and what is right. For the user this most logically would be whats left and what's right when they look at the open display. For Apple it may be when you look at the top cover with the logo in proper direction. They have odd priorities like that. :D
replyThey say it's the left and right ports when facing the left side of the Mac.
reply> It appears that the author is directly contradicting your read.
replyCorrect.