The house is already worth twice as much as the loan. It was sold well below value back in 2017, has been renovated since then, and prices have risen sharply again since then.
The roofer is coming soon because the situation apparently changed again; it might still be possible to repair it well. The roof itself is still completely fine (roofer's statement in 2017 during the inspection: This is solid work, it will last another 20 years or longer), it just seems to have one leak contrary to the initial assumption of the roofer and the drywall installer (there is a problem with the insulation renewed in 2017, which is why both trades are involved). If it can be repaired well, we will have it done and then "only" need to insulate again because the current insulation is now ruined due to moisture. But that is better than a completely new roof. That is 6,000–10,000€ versus 30,000–40,000€...
If anyone is interested in the whole story, I can gladly write it, but I would have to elaborate a bit more on the topics of insulation, roof and/or timber frame construction, and roof.