For example, one loan with €120,000 or similar with a 10-year fixed interest period and then trying to put the entire special repayment into this loan (additionally setting a generally high monthly repayment here)
For example, one loan with the outstanding amount (or possibly split again) with a 20-30 year fixed interest period (if desired) and then only paying down that one for the first 10 years with, for example, 1% (if possible, we had it renegotiated accordingly).
This way, hopefully, after 10 years you can fully redeem one loan, let the rest run smoothly because you secured the interest rate, and your monthly installment will then also decrease accordingly.
Have you calculated that? In your method, you then repay the loan with the lowest interest burden first. And at the same time, you pay high interest on the loan with the long term. This way, on paper, you buy yourself a long fixed interest period, but the outstanding balance after X years usually hardly decreases in total.
Unfortunately, I no longer have a current Excel sheet; in most cases, it did not pay off for us. Especially since the outstanding balance was not significantly lower even after the long fixed interest period expired. You really need to look closely at which assumed interest rate increases then lead to a better/worse result.
Unfortunately, people’s gut feelings are often very far off here, as we simply cannot correctly assess exponential calculations.