Pretty sure it’s just more of a hardware age issue. Smart TV makers don’t put much effort into their firmware, so if they don’t support a codec now they probably won’t support it ever. Devices made before a certain year probably won’t ever support H265. I suspect we’ll run into the same thing with AV1, unfortunately. It’s another objectively superior codec that will have compatible issues. 🤷

H265 is objectively superior in just about every way UNLESS you’re trying to play it on hardware that doesn’t support it. The only reason to use H264 is for broad compatibility.