Overheating CPU, is there a heatsink upgrade available?

My TV would randomly shut off and enter a power reboot cycle. I contacted support who had me try various troubleshooting steps, none of which worked. Eventually I opened up the TV looking for damaged components, but everything appeared fine. I pulled the original 2018 heatsink off and found the thermal paste was rock solid. After cleaning and applying new thermal paste, the TV started working without issue until just recently. I did use older thermal paste, so it might have been expired, but when I checked with my thermal scope the heatsink was sitting around 70C and seemed higher than it should be. This heatsink appears to just be a piece of metal, so I was hoping to upgrade it to something that cools a bit better. I have experience building computers and switching air cooled to liquid cooled CPUs, but this is the first time I am working with a TV, so I am unsure if the same techniques can be used.