An old tech shared this advice. "Replace the cheapest part first."
The capacitor issue is more about what happens on cold starting, your issue points to some other issue.
I have a Samsung UN60FH6003F. Last week it started shutting off like there is a power failure (no melody plays) and after a bit it will power back on ( with melody). I did some research and came upon the capacitor issue with Samsung TV's. I found a replacement power board and installed it but TV is doing the exact same issue. I have checked all the capacitors and none of them are bulging or leaking on either board.
I am lost and would love to get a new opinion on this as I am totally stumped.