So I consider a reasonable distribution of assets between cash, special funds, and real estate to be important. Over the past 100 years, it has always been best to own real estate. But of course, you also need liquid funds, for which money in bank accounts is quite good. Make sure never to have more than 100,000 EUR per bank in the account. If a bank really crashes, at least the statutory deposit guarantee will kick in. Otherwise, I currently consider it the smallest risk to invest the amounts of money that you do not need in the long term in an MSCI World ETF, because it contains 1,600 companies worldwide. Although I caught the worst possible entry point in mid-February, you just must not look at the portfolio. In ten or twenty years, the price will have risen significantly. And the price drop now for the MSCI World was not as big as it was for the DAX.
Otherwise, regarding the original question: The desire for such a regulation impressively shows the mindset of building sharks: They would love to write into every contract that they are the only ones allowed to get rich and that all risks must be borne by others. Therefore, I find building sharks extremely unsympathetic because they cheat both the builders and the craftsmen equally. Therefore, I would always tender and award everything myself, possibly with the support of an experienced site manager. That can also be a retiree who is happy to accompany such a project. Although they cost something, they help avoid trouble and can save more costs than they themselves cause.