Construction costs are currently skyrocketing

You actually need a backup generator for this - to be realistic, that probably won’t happen, you have other problems than watching TV anyway.

A backup power/emergency power supply using a generator would be a solution for me. A Honda EU 20i should be of good quality and help for several hours. Especially a monoblock heat pump is at risk if you haven’t installed any drain valves. I have none of that installed. I also don’t need an "automatic" solution. In case of a power outage, manually confirm a switch, then start the Honda EU. Something that simple? How does it work in practice?

Unfortunately, yes. Because no matter how great your information may sound, you should also mention the construction of new nuclear and coal power plants. And not just in China.
I cannot tell you how long fossil energies will remain cheaper; I have no crystal ball. But it would be nice if we took the first step before the second. We need energy to continue being at the forefront.

They are building new, more efficient coal power plants and replacing old plants with them. Just question why they are building new power plants :D The coal consumption does not increase further due to the new, more efficient plants.

...
Just questioning why they are building new power plants :D

and why are they building new coal power plants instead of using renewables?

and why are they building new coal power plants instead of using renewables?

Maybe because in China the sun rarely shines at night!? Maybe also because it’s about the mix, especially in a transition phase. If you can save limited resources through more efficient technology, why shouldn’t you do it, at least until enough renewable energy is available?!

A backup power/emergency power supply using an emergency generator would be a solution for me. A Honda EU 20i should be of good quality and help for a few hours. Especially a monoblock heat pump is at risk if you haven't installed drain valves somehow. I have nothing installed of that sort. I also don't need an "automatic" solution. In case of a power outage, manually confirm a switch, then start the Honda EU. Something that simple? How does it work in practice?

That really depends a bit on your situation. Do you have photovoltaics, photovoltaics with storage? Storage on the AC or DC side? But you can easily read up online, otherwise ask an electrician.

and why are they building new coal power plants instead of using renewables?

As I have already written, China is expanding renewable energies on a massive scale. Just this year, power plants with renewable energies are expected to be connected to the grid with the same nominal capacity as all power plants and energy sources in Germany combined. After this year, China will be able to generate seven times the amount of electricity produced in Germany from renewable energies. Seven times the amount! And this amount will continue to increase every year.