ᐅ Underfloor heating retrofitted by milling into the screed. Any experiences?

Hello everyone,
I’m urgently looking for people who have had underfloor heating milled into the existing screed/floor screed in their house or apartment.
Please share how long it has been installed, how satisfied you are with it, and which company carried out the installation. Maybe also what to watch out for and other tips.

Perhaps you know someone among your friends or family who has had this done and can tell me how satisfied they are.

Unfortunately, my heating installer advises against it. Mainly because the pipes are very thin, can easily get clogged, the screed gets weakened/damaged, and the heat distribution is poor since the pipes are installed quite close to the surface. Also, there is no guarantee or warranty provided, and so on.
Of course, a proper underfloor heating system would be better. But we cannot tear out our perfectly good, only 20-year-old screed, 100sqm (1076 sq ft), just because the milling-in system for retrofitting is not well known in our region (Bavaria/Upper Palatinate). It is also sufficiently insulated underneath.

THANK YOU for your experiences and feedback.

You often hear about the idea, but then nothing comes of actually doing it.
My guess is that very few people actually follow through.