Before attempting to flash any firmware, you must open your TV box to confirm the model number. Printed directly on the motherboard (PCB).
If you need help finding specific download packages, could you specify the printed on your motherboard, or let me know the exact error code showing up in your Rockchip flash tool? This will help narrow down the precise software build you need. Share public link
Based on community documentation, this specific revision includes: : Rockchip RK322x series (typically RK3228A/RK3229).