Retrofitting underfloor heating - decision support

Hello experts,
We have bought a ground floor apartment built in 2004 and want to convert the current central heating via district heating to underfloor heating.

Since we have no experience with such conversions, I wanted to ask for your advice here.

Which underfloor heating system should we choose? Screed milling or dry system with prefabricated panels.

If it is the dry system, which manufacturers are recommended? I am no longer able to keep track, as there are so many manufacturers like Roth, Knauf, Kermi, Thermisto, etc. who offer it. It would be really helpful to know from your experience which one we should take.
We have a ceiling height of 2.5 meters in the apartment and definitely want to keep the height as high as possible, even if it is done with a dry system.

I would be very grateful for any recommendation/tip on this.

We have purchased a ground floor apartment built in 2004 and want to convert the current central heating from district heating to underfloor heating.

If I understand correctly, you have bought a condominium. Is that right? If so, do you even have permission to access the screed, as to my knowledge this is common property.

Exactly right, the approval from WEG has already been granted, so no problem arises.

Which underfloor heating system should we take? Screed milling or dry system with prefabricated panels.

If it is the dry system, which manufacturers are recommended? I no longer see through it, as there are so many manufacturers outside (Roth, Knauf, Kermi, Thermisto, etc.) who offered it. It would really be very helpful to know from your experience which one we should take.

First of all, it is important to know the heating load. For this, supply/return temperatures of the heating system. With this, the spacing of the underfloor heating is calculated, etc. And then it does not matter what you use. More or less like deciding between a blue and a red car. Milling has the advantage that the height does not change. I would only do dry if the old screed is removed (or then directly properly wet).

What personally interests me is how you then handle the connection and calculation of heating costs. Heat meter before mixing?