I think Samsung TVs can be interacted with through HA's SmartThings integration but I don't use that at all. Instead I have my Harmony Hubs (yes, a dying breed, literally) connected and that's the only way I interact with my TVs via HA.

"Alexa, turn on Living Room TV" -> HA -> Harmony -> IR Blaster

I think through the Apple TV integration I can control them even further but I greatly prefer just using the Harmony remote. I'm not looking forward to the day when those stop working completely and I have to evaluate other options. Every year or so I look around but nothing beats my old Harmony remote (with a coin battery that lasts so long I've lost track, easily over a year) and the Harmony Hub (which actually sends out the signals).