Well, thermal performance in terms of silicon temperature is going to vary based on the heatsink of the card you get.
That’s going to be irrelevant to the heat introduced into the room - a larger heatsink will bring down silicon temperature, but you’re still moving the same amount of thermal energy.
What you are actually interested in is power efficiency, which is also missing from the article.
Based on average cards / without overclock: 5070 uses 250W 5070Ti is up to 300W 9070XT is around 305W
It stands to reason that a 9070XT will heat up your room more than the weaker 5070, but about the same as a comparable 5070Ti