You are following the explanation for the bans as they are told. R134a was introduced in the 90's, and in 2010's it conveniently is named bad at the same time

You are following the explanation for the bans as they are told. R134a was introduced in the 90's, and in 2010's it conveniently is named bad at the same time the patent runs out. So the savior was the 4x as expensive R1234yf, introduced 2012. Don't worry that it's flammable. Here we are 10 years after R1234yf, it's time to explain why it can't be used anymore!