Old building 1971 - What should/must be renovated?

Hello everyone,
we bought an old building (a semi-detached house) in Bad Honnef (20 km from Bonn / Rhein-Sieg district) 7 years ago.
We are a couple, both 33, and had a child last year.
The house has the following features:
- Solid house 108 sqm living space, 4 rooms, plus a basement
- Plot 300 sqm
- Purchase price 2014: 183,000 euros with a standard land value of 100 euros (2014), now: 250 euros (2021)
- We do not want to sell, a realtor estimated the market value last autumn at 330,000 - 350,000 euros

Renovation:
- 30,000 euros for the interior (new bathrooms, new tiles, laminate flooring, wall breakthrough, new doors)
- New garden in 2020 - 25,000 euros
- Roof renovated to KFW standard - after subsidies about 16,000 euros

Altogether:
183,000 purchase price, 20,000 incidental costs, 70,000 renovation = roughly 270,000 euros.

The loan was 160,000 euros in 2014, current remaining debt: 50,000 euros.

Features of the property:
- Plastic thermal insulation windows from 2002
- Oil heating with hot water preparation from 2007
Consumption BEFORE the roof renovation: about 1,600 liters/year including hot water preparation, so about 15 liters per sqm - although the basement is partially heated as well.
- Electrical system already with FI switch
- Roof renewed in 2021 to KFW standard
- New bathrooms in 2014
- All rooms newly fitted with laminate or tiles and newly painted.
- Thermal insulation facade with 5 cm
- New facade painting from 2014
- Pipes made of copper - according to a relative heating installer no need for action

My question:
We have everything inside now as we like it very much. But that is superficial.

Is there anything that makes sense to address currently? Or anything we should be worried about?

Is there anything that makes sense to tackle at the moment? Or anything that should worry us?

If otherwise everything is technically okay or to your liking, you could insulate the basement ceiling for very little money.

If otherwise everything is technically okay or to your taste, you could still insulate the basement ceiling for very little money.

The facade insulation of 5 cm is enough or probably not worth redoing, right? It takes too long to amortize the costs, doesn't it?

The 5 cm facade insulation is enough or probably not worth renewing, right?
It takes too long to amortize the costs, right?

Yep. Better to tackle the basement ceiling. Or renew the windows - besides saving energy, it leads to less cold panes and thus a more comfortable feeling when sitting next to a window (I don't know what the situation is like for you).

Do nothing at all.
Replacing windows from 2002, what's the point?
Insulating the basement only makes sense in combination with a thermal insulation door to the basement.
As a rule, the stairwells are open though.
Of course, you lose ceiling height in the usually already low basement with that construction year.

I would relax if I were you .

Nothing, unless there is a clear technical problem, or something where you feel really uncomfortable.

The oil heating system could be kept an eye on. The CO2 tax is rising massively. But here too, I would wait until the thing is broken and only then take care of it.
If it is opportunistic in terms of funding and you can really use the space gained by removing the oil tank, feel free to get rid of it earlier.