You can now unlock the bootloader of your third-gen Fire TV Stick, flash a custom recovery, install Android TV 11 and much more!
Android TV Android Police
How to install Android TV on a Fire TV Stick
ROM][UNOFFICIAL][11] LineageOS 18.1 for Fire TV Stick Lite/3rd gen (sheldon/p), Page 12
Fire TV Stick (3rd Gen) gets Android TV 11 with unofficial LineageOS 18.1
ROM][UNOFFICIAL][5] LineageOS 12.1 for Fire TV 2 (sloane)
fire tv Android Police
LineageOS 18 XDA Developers
Fire TV Stick 4K Prerooted and Debloated Android TV Rom (6.2.7.6) : r/fireTV
ROM][UNOFFICIAL][11] LineageOS 18.1 for Fire TV Stick Lite/3rd gen (sheldon/p), Page 11
Así puedes instalar Android TV en tu Fire TV Stick de
Fire Sticks & Android TV Box
ROM][UNOFFICIAL][11] LineageOS 18.1 for Fire TV Stick Lite/3rd gen (sheldon/p), Page 20
Fire TV Stick (3rd Gen) gets Android TV 11 with unofficial LineageOS 18.1