Forward loan - Secure interest rates now?

Yes, better do that, at some institutes the processes have not kept up yet. There A doesn't know what B is doing.

Calling doesn't cost anything and I would look for the cancellation confirmation again.

The old bank must make you an offer, regardless of whether the loan is paid off or not.

Because if the payoff (for whatever reasons) fails, the old bank would not have fulfilled its duty (to offer continuation) and could possibly be liable for damages (in the case of rising interest rates).

And the wording of silent acceptance was sometimes customary in the past, but only applies to old contracts. Today it is no longer legally permitted (though it used to be).

A completely different question, for example, if at the time of the follow-up financing I still have 170,000.- outstanding (to be financed), would the banks also already conclude a forward loan for 200,000 now, leaving the purpose of use aside, so whether a pool is still to be built or a world trip is planned, that should be basically open, as I do not want to commit myself 5 years in advance about what exactly I will use the money for. From the lending perspective, a house that is currently worth about 350 k€ on the market should still be able to be encumbered with 200 k€ in 5 years...

if it fits within the framework condition.

you would have to apply for it that way and have it checked

In terms of lending, a house that is currently worth about €350k on the market should still be able to be encumbered with €200k in 5 years...

Depending on the bank's internal guidelines, you could already fall out of the 60% condition. But has already given the right tip.

That the loan-to-value ratio may possibly be over 60% is okay and not a problem. With a blended interest rate of currently 3.x %, we would probably still be significantly cheaper...