ᐅ No heating system is being approved?!

This summer, I bought a condominium. I was informed about the age of the gas boiler and had already factored in the modernization costs for a condensing boiler. Now, the old heating system has broken down, and, as absurd as it sounds, I am not allowed to install a new one.

The problem:
The apartment is part of a terrace house, so chimneys are generally not possible.
The old gas boiler was installed on an outside wall without a chimney.
According to the local chimney inspector, modern condensing boilers are not permitted to operate this way, and he would not approve one installed like that.
Old gas boilers that had this exception for outside-wall installation are no longer produced, according to both my heating technician and a second specialist company.
Chimneys on the outside wall are not approved because, due to the terrace construction of the houses (my apartment is the lowest of four units), they would need to be incredibly tall, according to the city building authority.
Next week, there will be an on-site meeting with the chimney inspector and the city building supervision to look at the problem.

Unfortunately, this doesn’t make me warm either...

Can anyone offer advice?
I’m sitting here frustrated with two cold children, using an electric fan heater in one room, and unable to enjoy the beautiful large apartment because it’s cold.

Thanks in advance for all helpful comments!

What about electric heating?

Thank you for the quick response!

Electricity is the most expensive way to heat, right?
I actually wanted to continue using gas if at all possible.
I have the gas connection and the radiators.
Otherwise, I would have to retrofit electric heaters everywhere.

You could install a small air-to-water heat pump with a split outdoor unit in that spot and replace the radiators with low-temperature ones. It depends on how much space is available; you would probably also need a hot water tank.

"It's not possible," is what the chimney sweep quickly says, but he doesn’t offer a solution either, right?

Chimney sweep, indeed.
I'm not the only one who receives a dismissive response without a solution from a chimney sweep.
The profession is not well regarded by several people I know...