Hey! Good points, I actually made a forum post about this exact topic: splitting Persia into Sassanids, Seljuks, and Safavids.
The current Persians clearly reflect the Sassanid Empire, but they don’t cover the 1400+ years of Persian history after the Muslim conquest, especially the Seljuk and Safavid eras with their unique warfare and identity shifts.
Feel free to check it out if you’re curious, would love your feedback!