Gas tank instead of district heating?

Hello, we have finally found a plot of land, unfortunately there is no gas but only district heating and since no one knows how long it will still be available here, I am considering what to do about the heating and wanted to know your opinion. The house is planned with a condensing gas wall heating system with solar energy system and a bivalent 400l storage tank and 3 flat collectors. Now I am basically forced to buy a gas tank which then has to go into the ground somewhere, otherwise such a huge tank in the garden really looks forbidden! What do you think about that? Advantages disadvantages? I have already read a bit about it and would buy the tank, not rent it. Or should I completely redesign and install a different heating system? The house is 113sqm, there are two of us. Thanks in advance for your opinion.

Hello,

...Or should I completely redesign and install a different heating system?

There are certainly alternatives to consider: Instead of gas + solar thermal system => air heat pump + photovoltaics or air heat pump alone, or air heat pump + improved insulation...
With liquefied gas, in addition to the tank issue, it should be noted that the low modulation values (minimum output) cannot be reached due to the higher energy content. Therefore, gas condensing boilers running on liquefied gas cycle particularly heavily and frequently.

Best regards

mhh and if after 6 years the air heat pump breaks down I have to invest a lot of money again, right???