I do not know what boiler you have, this does make a difference, but basic idea is the TRV showily reduces flow as room warms up, either forcing more water though the other radiators, or lifting the by-pass valve, this will then return warmer and warmer water to the boiler, if the boiler can it will then reduce output, and once it can't reduce output it will start to cycle off/on in what is called the mark/space ratio.
But what it can't do is switch the boiler completely off when warmer weather arrives, so we put a thermostat in a lower floor room, as heat raises, in a room normally kept cool, as don't want the boiler to fire up in the morning if it is likely to be a warm day, with no alternative heating, this includes the sun through windows, and no outside doors.
Don't know your house, but my house no such room. So often next best thing is the hall, but fit a TRV so it can reheat fast, but TRV closes before the thermostat is triggered, so thermostat stays always on in the winter.
But although that would work if we keep rooms heated 24/7, we don't, so now looking at speed, so the lock shield valve setting becomes important, and really better if we monitor at least two rooms, in real terms one with thermostat in, and one with a linked TRV head, of course ideal is every room with linked head,
a central hub where you can control each room would be the bee's knees, but Honeywell EvoHome is not cheap, so in non main rooms,
Using stand alone programmable heads is likely good enough, the one shown is bluetooth so if two used in same room they can be linked. Also it can connect to one phone so can control from phone when close enough, there is also the Terrier i30
which does not have bluetooth option, showing picture as it shows what adaptors come with both makes, I paid £15 each for bluetooth eQ-3 in 2019 before brexit, prices now seem to have gone up.
Yes without linked TRV heads setting up the wall thermostat and the TRV can be a bit fiddly. This house my problem is hall cools too slow, mothers house it worked A1, the wall thermostat was set about 1.5°C higher than the TRV, heat raises and the wall thermostat is higher than the TRV, and on warm days the wall thermostat would switch off, on cold days the boiler would modulate (turn down) so there was hardly any hysteresis in the temperature.
this picture shows what hysteresis is, and any on/off thermostat must cause some hysteresis, but with a gradually opening or closing of a TRV or with thermostats connected to the ebus (Most common is OpenTherm) we get this
at least that's the theory, my boiler does not modulate, it cycles instead, that's common with oil boilers, however it still works with TRV control, the wall mounted thermostat is basic there so I can turn boiler on/off without going outside and walking down the steps to under main house where the boiler is, and it also connects to mobile phone, so when away from house heating auto turns off, but most the features have been turned off, and my boiler does not support OpenTherm, very few oil boilers can modulate, only gas tends to do that.