MSW is not a sine wave so by definition there will he issues.
SMPS are harder on capacitors than linear supplies so failures will be more common.
A well designed SMPS should have a reasonable life cycle.
The input capacitors of a SMPS see 100,000 pulses a second. It doesn't seem like another
120 a second from the power line would have a major effect.
Attached is a scope trace of the charge current of a 9W LED lamp on grid power, only thing
I have on file. As you can see there is a rapid rise in current once line voltage reaches
the charge of the capacitor. That rise would be even faster if not for the internal current
limiting series resistor. In a typical power supply this rise would be even faster since
there no resistor. There are surges even with a pure sine wave. I just don't believe a
square wave would be an order of magnitude worse.
You could run the TV on DC like I do. Use an external bridge rectifier and capacitor. No
pulses with DC. It would require a good internal knowledge of the internals of the TV,
some TV have voltage doublers and that wouldn't work. PFC controllers were supposed to be
the thing of the future but haven't seen many.
If this really bothers you, a 10 ohm series resistor might be a solution. The SMPS would
easily handle the slightly lower voltage and the resistor would lower and extend the surge
current. Something for the peanut gallery to discuss. I'm not sure it would increase life
expectancy of the capacitors. It certainly wouldn't damage anything, just waste a little
power. If it helps you sleep at night that may be sufficient.