Latest Amazon Fire TV (2021-2022) user agents:

User Agent	Browser	Platform
Dalvik/2.1.0 (Linux; U; Android 9; AFTANNA0 Build/PS7714.5503N)	Android Browser	Fire OS 7
Dalvik/2.1.0 (Linux; U; Android 9; AFTANNA0 Build/PS7712.5370N)	Android Browser	Fire OS 7
Dalvik/2.1.0 (Linux; U; Android 9; AFTANNA0 Build/PS7713.5443N)	Android Browser	Fire OS 7
Mozilla/5.0 (Linux; Android 9; AFTANNA0) AppleWebKit/537.36 (KHTML, like Gecko) Silk/128.6.1 like Chrome/128.0.6613.194 Safari/537.36	Mobile Silk 128	Fire OS 7
Mozilla/5.0 (Linux; Android 9; AFTANNA0) AppleWebKit/537.36 (KHTML, like Gecko) Silk/130.1.71 like Chrome/130.0.6723.86 Safari/537.36	Mobile Silk 130	Fire OS 7