Yes you can, but I experience the sound being off from the voices. I use the Amazon 4K FireStick as well. Audio lag is so noticeable, that I end up using the pre-installed apps instead so voices are in sync with mouth. Wish this could be addressed.
We are still experimenting with it but we tried a friends Amazon 4K and we did get our Disney Plus, Amazon Prime and Netflix, However we are not getting our cable tv channels to work. We were able to download Netflix and Amazon so we don't need the fire stick. Disney needs the firestick..