Buying a house with rendered walls built in 1960, what should you pay attention to?

Clinker bricks themselves do not insulate at all.
In view of converting the heating system to a heat pump, insulation must also be considered.
Heating an unsanitized house with a heat pump would be a very expensive idea.
With 200k you can get pretty far.

But whether one can achieve the mentioned goal (new building standard) with 200,000€ in this project? Except for a part (clinker bricks do not insulate & are supposed to be removed) of the foundations, nothing is preserved. Hazardous substance remediation is excluded at this cost. In this case, it will surely soon be cheaper to tear down the house and build a new one – or not buy it at all.

But whether one can achieve the mentioned goal (new build standard) with €200,000 in this project?

A goal that, in my view, is not even desirable here - but I remind you that we have not yet seen anything that could provide professional assessments.