I have 3 pixel 9a with graphene. each has different meory / storage chip manufacturers. I haven't touched the other two phones yet but my first 9a is giving me tons of black screen issues that need to be rebooted by holding the power button for over 60 seconds. It is a daily occurrence, sometimes multiple times.
If anyone else notices a freeze or black screen, please report here. I will play more with the other 2 9a's to see if they also have issues.