Acceptance of Common Property - Defects/Outstanding Work

I'm sorry, but it will probably go like this: a few simpler defects will be fixed by the subcontractors who currently have nothing better to do. Most will not be fixed, and the construction company, which I suspect is a developer that founded a GmbH specifically for the construction project, will ignore any defect complaints and deadline notices, etc. This GmbH will either be liquidated or placed in other mailbox companies (simply as a delay tactic) since the business purpose (construction of the project) is completed with acceptance. Eventually, it ends up abroad, preferably a Limited, and this GmbH has no money left. So even if you eventually win in court, the claims will be offset against the capital contribution of then only 1 GBP, and that's it. Unfortunately, this happens frequently, and there is nothing you can do about it.

Sorry, there are a total of 21 parties.

That is a whole housing complex. Hopefully others were smarter and withheld more than €5,000. Who was in charge or had overall responsibility for the project?