House purchase is upcoming, EURIBOR surprise?

Good morning!
We have been with a well-known financing broker for over a year and are about to finalize a contract with the bank. Originally, we wanted to build, but now a property is being purchased, I hope I may still ask my question here.
We consulted the broker for several projects and properties and were shown various scenarios; these offers were provided in writing with a repayment plan.

A brief overview of us and the offer:
Object: Semi-detached house for €255,000 in a major city and good location
Loan requirement €262,500 (including property tax, notary, modernization, equity of €18,500 taken into account)
Income €4k net fixed (+€250-500 variable from a side job), trend rising, as both are still early in their careers.

The requirement was a 15-year fixed interest rate, around a €1,000 installment, preferably below that.
We have now received an offer of 2.54% for 15 years; an installment of €1,000 would correspond to a 2.06% repayment rate.
Special repayments of 5% are possible, but a maximum of €1,100 annually—not ideal, but I could live with that.

The offer sounds good to us. This morning I read through the contract to prepare for the appointment and saw under one point that the nominal interest rate is adjusted every 3 months according to the Euribor. Directly underneath in the contract, however, it states that the effective interest rate is 2.54%.
Now I naturally wonder what is going on: Does the interest rate adjust every 3 months based on the market situation, or is the 2.54% fixed for 15 years, as we requested?

Does anyone have experience with such a contract setup? I will address this during the conversation, but I find it very strange that not a single word has been mentioned about it so far and wanted to get a "third opinion."

Either fixed interest rate or adjustment to Euribor.

Both together are not possible.

If you want, scan the contract and send it to me (preferably redacted) via PM.

Either you misunderstand something or someone is trying to sell you a lemon for an apple (or you are talking past each other).

Thank you for the hint and your offer. That's what happens when you read a contract before the first coffee. This Euribor clause refers to the interest rates AFTER the fixed interest period 2030.... I am just very suspicious and so far cannot believe that we have been well advised and that everything will run smoothly, maybe I just wanted to find something.

It's fine... better this way than the other way around and ending up on your a** later on.

Whether you were actually well advised, you only see once the place is completely paid off.

Before that, you can only gather opinions, and that requires more input. But that wasn't the topic.

Special repayments amounting to 5% are possible, but a maximum of €1100 per year - not great, but I could live with it.

That somehow doesn't fit, does it?

Sometimes you have to have trust as well. I think it happens more often than you believe that everything just goes smoothly ;-) Healthy distrust is okay, but it shouldn't lead to questioning absolutely everything. Sometimes you should just listen to your gut feeling.