What they all miss is the rails mean absolutely nothing to the thermals of the phone, the heat was never released actively through the rails, the heat was released through the glass after it had warmed it up and then the metal was just an easy exit point once the glass was hot. The Ti does nothing here, it does not make it better or worse.
The mid frame change to have that massive center punch cut out for the Qi 2 charger is the real issue, so the chip is loading heat into the mid frame but it has less surface area for which it can conduct that thermal load, and thus becomes more localized and thus more felt as a hot spot. So had they not caved to the replace back glass effort and keeps a full size mid frame, thermals would be the same...
I bet, if I took a iPhone 14 pro logic board and put it in the 15 pro mid frame design it would exhibit the exact same failures and hot spots as the 15 pro does now even worse, I think they leaned in on the 3nm power, and heat reduction under normal duty cycles and whoops, the P cores are awake for way more things at low use than they knew for not apple tasks. So we have been carrying around the bug, for a long time now, it was just masked with a big mid frame spreader bar.
So how does apple fix this, they make the phone 2.5mm thicker, restore a full size mid frame, and boost the thermal conduction layers / heat pipe to the rails on purpose and not on accident as it is part of the mid frame