We don't disagree because that's exactly what they were.I think this is one of the things we disagree upon, or we misunderstand each other: Iazyges weren't the Sarmatians, but Sarmatians amongst other Sarmatians. The "Western branch", if You want.
As the Roxolanes (who were Sarmatians too).
You said the Sarmatians never settled in Pannonia then went on to say the Izagyes did .......... I simply stated the Izayges were Sarmatians.
Sarmatians were the peoples as a whole, you had Sarmatians from the Russian steppes all the way to Panonnia, they were not ruled by one king.