How did you find such an engineer with the applicable expertise?

The same way you hire a company for any service, start by searching for local structural/construction engineering firms and then call a few and ask if they’ll do an inspection on a residence.

If you personally know any architects or general contractors in the residential market, they should be able to recommend someone.

Selling a house in Denmark requires the seller to acquire a “condition report” from a certified inspector. The report is valid for 6 months and costs around $1000. This also ties into the optional “owner transfer insurance” which covers serious defects / building code violations undetectable by the inspectors. The insurance lasts 5 years and costs $2000-$5000

In the US afaict inspections are a plus but not required for sellers to provide. Lots of people were waiving their right to inspection in order to make their offers on houses more attractive to buyers. Kind of a stupid thing to do, but people had low interest rates and were desperate to buy

What did they find that was so bad?

1895 house in Oakland with a soft story condition and a dining room that was cantilevered out over the aisle. It was listed for something like $850k in around 2018, so kind of cheap! But correcting the soft story and the rest of the framing would have been astronomically expensive. He guessed something like 400-500k, and now having experienced home renovations, I am fairly certain he was in the ballpark.