ᐅ Integrating Radiant Floor Heating / Underfloor Heating Effectively

Hello dear house-building forum,

I’ll admit right from the start: I’m a complete novice and am just trying to understand or supplement the existing planning so that we end up with a sensible result.

Here’s our situation:
We bought a single-family house from 1994. The previous owner apparently installed underfloor heating on the ground floor themselves, together with a "colleague," so unfortunately there is no documentation available. In the bathroom, there is a regular radiator plus additional underfloor heating, most likely original from the build year. In the utility room, there is only a regular radiator. The other rooms on the ground floor have the mentioned underfloor heating. There are 5 heating circuits, controlled so far via thermostatic radiator valves (TRVs) located where the old radiators used to be.

We now want to install underfloor heating in the upper floor as well, controlled via a heating manifold with wireless room thermostats. The other radiators will be replaced with low-temperature radiators, so that the overall supply water temperature can be lowered and the system can be more easily retrofitted with a heat pump in the future.

How would you recommend proceeding with the situation on the ground floor and the existing TRVs? Ideally, we would like to no longer need these and to remove the corresponding valves entirely. So far, we have been told that this might be difficult because they may still be needed (to ensure enough heat reaches the upper floor and that the lower floor can be regulated down?). Or is there a solution without TRVs, simply setting a central temperature for the entire ground floor? One temperature for all rooms (except the bathroom, but we could always turn up the radiator there) would be sufficient, since the living, dining, and kitchen areas are all open plan anyway.

Or, if it’s better to keep the TRVs: is there a way to "hide" the valves inside the wall? Like inside the manifold box? If so, what would you recommend?

Or would it be more practical to try installing a supply water temperature control with the now lower temperature on the feed line, and then regulate this with individual wireless room thermostats?

What would you recommend?

And apologies if I’ve misunderstood anything.
If you need more information, please feel free to ask.

RTLs are still required for hydraulic or thermal balancing.