Question How to hide my fire sticks mac address

Mac addresses never leave your house. It might be possible to change the mac address but it depends if the software allows it. Maybe if it was hooked to a pc you could do it.
There likely are tricky ways to use a wifi repeater/bridge to make it appear that all traffic is coming from that devices mac address rather than the stuff connected behind it. The only reason I have ever seen to do this is when someone was trying to use it in a hotel and you could not directly use the hotel wifi. Mostly because you needed to respond to a web page which pretty much only worked with a pc.
 
For hotels, I use a GLI.NET travel router.
  1. Log into hotel wifi with my laptop like normal. Make sure you accept the guest login prompt and your laptop has full access to the internet.
  2. Clone laptop MAC address onto my travel router.
  3. Set travel router to broadcast my own wifi network with my own SSID and password.
  4. Connect tablets and Firestick to the wifi travel router.

That's how I'm able to watch Netflix while traveling.