How to change the vanilla crosshair to custom

Hello, I tried to find something similar on the forum, but found nothing.

I would like to know if there is any way to change the vanilla crosshairs to custom, for example when you pick up a certain weapon or item.
I'd also like to know if there's any way to add custom sprites to the screen.
For example, I want to add a cooldown ring around the crosshair that should also appear when picking up a certain weapon.

Thanks in advance.