Not all brands sell these features as a subscription.

I chased this up with Ford over my car. They said we get them for free for the life of the vehicle, and as long as the 4g it needs to work exists. That's got atleast 10 to 20 years left in it.

That's exactly what I use remote start for. Just leave your car set to 68 or whatever and then when you remote start it will come up or down to temp. Even on my cheapass Chevy that's 10 years old I can remote start it (including the HVAC) and also hold the "unlock" to start the defroster. Now I can't actually change the temp the system is set at without getting in the car, thats true, but that's a real edge case for me when I can just leave it set at room temp pretty much year round. Even the seats and steering wheel will heat up if I left that on beforehand. But maybe you do have a real need to tweak the temp and A/C values on the daily where you live, rather than just have the car resume where you left it at, I wouldn't know.

nah, pretty simple. set the preferred settings in the menu in the vehicle, then have a fob button to activate it. flash the lights to signal acknowledgement, just like locking and unlocking.

although maybe don't actually flash the lights, since everything is stupidly over bright LED now and it's rude af to be using those unnecessarily

My car has a timer to set the cabin at a given temperature by a given time, do you know if your car has a function like that?