decentralized ventilation - various manufacturers

I do not know the Dimplex. I do not think much of these compact units with multiple connections because the heat recovery (HRV) is usually not very high. Another point is the noise level in the room where the unit is installed. I also do not like that in winter operation, the unit starts to increase exhaust air flow for self-protection against freezing in order to keep itself thawed. This only works up to a certain point; then it switches off and tries to thaw itself again through the exhaust air. During this time, there is no properly running ventilation. However, this applies to all units with cross-counterflow heat exchangers that do not have preheating.

I was recommended the Dimplex DL 50 WE by the responsible ventilation planner, does anyone perhaps also have experience with this?

My favorite would actually be the Meltem since there is a KNX-capable version available, what are the opinions here?

I am also interested in both. The Meltem M heat recovery unit because it is KNX-capable, has radial fans and electric closure caps. The Dimplex because it is significantly cheaper.
Does anyone perhaps have experience?

Another point is the noise level in the room where the device is installed.

There should be quite a few differences between the models.

I am afraid that the noise differences are less pronounced than one would like... we could hear a ventilation noise in all the devices we inspected - whether Inverter or Kreuz.

What I have read so far is that the inverters are supposed to be more annoying because the noise changes every 1-2 minutes. That sounds plausible to me at first.

Is it the case that a decentralized ventilation system generally operates with inverters?
By inverter, I understand the following:

For example, in the large open-plan kitchen and living room, there are two devices, one by the kitchen and one on the other side in the living room.
On one side, air is blown in, and on the other side, air is blown out.

After 60 seconds, this is reversed, and where air was previously blown in, it is now blown out.
This should help prevent drafts because the airflow is constantly reversed.
On the other hand, this is necessary because (a general contractor told me) after about 60 seconds the heat recovery at the air-in blowing point is "used up" (too much cold air flows in). During the reversal, this spot can warm up again due to the now outward-blowing warm air and will reheat the incoming cold air during the next interval.

Are there also systems that have a permanent constant flow? If yes, how does heat recovery work there?

Yes - with a cross-flow heat exchanger... air is transported out and in within one device. Warm air is passed by cold air to heat it.