I started out with just toggling the TRV between two target temps which is pretty much your suggestion, 17° when I'm away, 20° when I'm home. I added better thermostat to the mix because I liked the idea of using an external thermometer for deciding wether to heat the room or not, instead of the one built into the TRV sitting right next to the radiator. So better thermostat usually overshoots the target temp a bit at first to get the TRV to open the valve fully. I don't even know of I like this tbh, but even in the old setup it would've been annoying to enter the kitchen in the morning to find out it's still 17° because something is broken with the whole setup. I mean before, I just went to the kitchen and turned on the heat manually before using the bathroom and putting on my clothes back in the sleeping room, and I'm still not sure the current automation is that much of an improvement even if it works reliably. Once you start you realize it's really hard to create automations that are subtle yet useful, and still easy to override, because there's always some special cases.