My main concern really is with the apple pencil and how well it will perform with a screen protector.
I've had a tempered glass protector on my 10.5" ever since I unwrapped it.
I know the debate will go on forever, but, I have seen no deterioration in display, sharpness, color, anti-glare or performance with the protector on.
I use my pencil quite often and the protector has no effect (positive or negative) on usage or writing.
My $0.02 is that there's nothing "bad" about having the protector on.