Sometimes, you just need to wipe custom settings and start fresh. Reinstalling the original firmware achieves exactly that.
The is a common Chinese-manufactured "universal" Android smart TV motherboard (chassis) used in various budget TV brands like Sunny (e.g., model hktrt2841p631 firmware
If you choose this path, look for target/ramips/mt76x8 in the OpenWrt source tree and adapt the device tree source (DTS) file. If you choose this path, look for target/ramips/mt76x8