Not automatically, at least in the US.

The Magnusson Moss Warranty Act protects against that kind of thing.

If you modify function A, and then make a claim for warranty service for a defect in unrelated function C and they don't want to cover that because of the modification, then: The onus is on the warranty provider to prove that your modification of A caused the defect in C before denying the claim.

And they know this. The first layer grunt on the phone or in the chat box may think it is some other way but the larger organization definitely knows what their responsibilities are.

Why would it?

To the best of my knowledge, changing software does not cause damage to the TV that could result in warranty being voided.

If the new software burned pixels or did something like that, which I am unsure is even possible from software, then I believe that would cause the warranty to be voided as a result.

But the reason would be pixels being burnt by using the hardware wrongly (i.e. through a bad software). Not merely by installing the software.

Might be dependent on where you live. But regardless, a factory reset puts it back to stock so they'd never know. If the TV is so badly fried that you can't reset it, they likely wouldn't be able to determine it in the first place.