Apple TV doesn't turn ON Tv Samsung

Hi!

I recently received as a gift an Apple TV. I used for many years an amazon fire stick 4k and his remote used to control my TV Samsung and Hi-Fi too without any problems.

First of all I noticed that I cannot control anymore the Hi-Fi. I had to "program" the turn on and off on the Mute button.

Anyway, the most important problem is that when I want to turn the system off, the remote works correctly turning off Apple TV and the Samsung TV. If I try to turn Apple TV and TV on in the next 20/30/40 minutes it works perfectly. But, if more time passes (like one day or many hours), it doesn't work anymore and I must take the TV Remote to turn this one on.

I tried everything, plugging into different HDMI ports, turning on and off the HDMI-CEC option on the tv but nothing seems to make it work on the long term (as I said, if I try immediately or in the short term it works fine). It seems like the Apple TV will "forgive" the TV in some hours :-)

Anyone can help me or anyone has the same issue?

Many thanks!