Which heat pump to use in monolithic construction?

With photovoltaic, heat pump and optional ventilation system, a house is equipped in a modern and future-proof way and can largely do without fossil fuels. There are certainly alternatives, but in my opinion gas tanks and solar thermal systems are not among them. Especially not in new buildings. Ventilation is comfort, photovoltaic pays off by itself, heat pumps should be well planned.

That says it all, except for the addition that a ventilation system is a huge gain in comfort.

A house with pellets is just as well and future-proofly equipped. However, the most economical option is still gas with solar.

And above all, heat pumps are not very durable, the technology is not mature, especially inverter-controlled systems.

So there are many opinions when it comes to heating technology, only the one from the initial post is definitely wrong.

The statement about what is economical is a "depends". Saying gas in general is just as wrong as saying heat pump in general. Similarly, the statement that air-to-water heat pumps are not sustainable is a really peculiar statement, which is at most useful at the regulars' table.

Regulars' table is often not that bad, although generalizations are made, they are very often correct. But you can also calculate everything nicely, I agree with you on that.

If you go by the majority, my statements are 100% correct.

Okay. Which sources do you use for your statement? Tip: the neighbor has an acquaintance who heard... is not a source. It is ALWAYS a case of it depends. And heat pumps have been around for a very long time. On the other hand, there are manufacturers of gas heaters where a no longer available component led to the replacement of the entire heating system. After about 10 years. At the regulars' table there are usually opinions. Rarely facts.

a no longer available component led to the replacement of the entire heating system. After about 10 years.

Well, it's no different with heat pumps. However, a heat pump is usually replaced faster than a gas boiler. But that doesn't help the OP. I would go for an air-to-water heat pump. With a central ventilation system. Then save money elsewhere in order to have the funds for the ventilation. Under no circumstances would I rely on air slots in the windows (window rebate ventilation). You don't buy absolutely airtight windows just to cut holes into them again.