If you delete the Tesla app and only use Remote S to start the climate, does it work better?
It makes no difference which app I use, including Visible Telsa, Teslafi or a direct REST request from a computer, or any of the phone apps. I'm pretty sure the problem is in the car, especially given the slow start up of climate even manually.
It is intermittent also - lately, I never know when it is going to work.
50.2 Firmware.