Heating type for old buildings - pellet or oil condensing boiler

Hello,
my name is Rainer and I intend to install a heating system in my house, which is currently heated with oil stoves.

My question is which type of heating system I should use?

Key data of the house in question:
Year of construction 1970
2 floors with 90 sqm each, whereby currently only one floor is inhabited by 2 people
Thermal insulation has been partially carried out (roof, window renewal on one floor, otherwise according to the year of construction)
2 oil tanks are available and can continue to be used; if the oil tanks are removed, there would also be space for a pellet storage

A gas heating system is excluded, as there is no gas connection, likewise a heat pump with underfloor heating is not an option since the floors are not to be renewed.

Thus, in my opinion, a pellet or oil condensing boiler, or possibly a high-temperature heat pump are options.

However, I am not sure whether the technology of the high-temperature heat pump is already mature and whether it makes sense for a not optimally insulated house?

I would also like to mention that I am occasionally not at home for 1 - 2 weeks for work, so a low-maintenance heating system would be sensible.

Thanks in advance for the answers.

I would stick to oil. Oil has the advantage that it is proven, low maintenance, and if you buy properly, also quite inexpensive.

Sorry if this sounds a bit drastic now, but: I personally find it cruel to heat with oil. We need petroleum for so many important (medical) products. If you already have a choice during a renovation (and many tenants or buyers of used properties do not), then an oil heating system should be the absolute last option. (The above is not to be generalized for all fossil fuels. Natural gas can ultimately only be burned or replaced in the medium to long term by biogas or synthetic gas.)

With all idealism, but I would also install an oil burner here, provided that is allowed. It would cost a few thousand euros at most compared to the disposal of the oil tanks and the investment in a pellet heating system. It will be expensive enough anyway, after all, radiators have to be installed everywhere if oil stoves were there before?

I am actually an enemy of oil as well, but I would also recommend it. Three more questions: is gas possibly planned in a few years? What exactly will be renovated/refurbished? Are the oil tanks really still in good condition?

Thank you very much for the feedback.

I am currently a bit uncertain about the further price development of oil in light of possibly increasing taxes, as suggested by the SPD in the exploratory talks. Generally, the trend seems to be moving away from fossil fuels, though the question is how fast all this will happen?

Since the house is not in bad condition and some things have already been renovated, this year I currently only plan to have a heating system including radiators and pipes installed, along with renovating the bathroom, besides some smaller things.

According to a heating engineer, the existing oil tanks can continue to be used.

A gas connection is unlikely to be possible in the future due to the rural location, and I lack the space on the property for a gas tank, so this is not an alternative.