Why don't you have a short layover in SIN or BKK and purchase the TV there?
As long as it is inside the limitations for size/weight for a single piece of luggage you either pay nothing extra or whatever fee the airline wants depending on your class of service and status.
The extra fees for one short sector should be lower than the fees for several sectors - and electronics are usually relatively inexpensive in BKK and SIN.
Also the risk of damage should be lower.

Another alternative is packing the TV in a wooden box, but this would add to the weight and the size.

The Thai size limit is 158 cm (add the three dimensions). You will be over and need to pay extra.
Also in economy you only have 20 kg per person.

But considering all these issues, did you check prices for TVs in Burma?