Offer evaluation for banks

Yes, with banks that allow this line of thinking, that might work.
My experience is: with direct banks, you just simply fall through the cracks if it doesn't fit into their plan. It's a shame, because they often have the best conditions.
And with the second-best bidders, the "Front Office" promises you that everything is wonderful, but after submitting the documents, the anonymous Backoffice comes in, which is not distracted by any indulgence.

I think anyone who wants to tackle tight and difficult financings in structurally weak regions actually goes to the local Sparkasse. They are, nicely put, the ones most likely to be persuaded.

One quick question beforehand, did the OP add his annual income only afterwards? Otherwise, I don't understand some of the discussions here. Interest rate, special repayment, outstanding loan amount are almost irrelevant then.

The thing is almost paid off in 10 years if you really put in the effort and push hard for 10 years.

The conditions for the mixed annuity loan are probably quite market-conform. I come up with the best offer based on your data at 2.13% with Signal Iduna if you put everything into one loan with a 15-year fixed interest period. Your mixed interest rate should even be slightly better there.