Net cold rent lease contract clause for real estate loan

Well. It is common practice in all the industries I have worked in so far that you are constantly told "yes, on paper it is like that, but in practice no one does it that way."
Which is not a legally binding argument, of course.
If you are from the respective industry, you can usually categorize such statements, whether it is 20 years of practical experience, or just talk because someone wants to sell you something...
But I am simply not from the industry.

Anybody from the industry here, by chance?

Honestly, it doesn't matter at all what anyone from any industry claims. YOU sign a CONTRACT and you have to stick to it if in doubt. And there’s no "they said that in the industry they don’t take it so literally or something" that counts.

Some requests just make you shake your head.

Is this purchase for you one of many transactions you make in this range? Or the biggest investment of your life? The second question is also simple - what can you lose, what is the risk? A worst-case scenario would probably be that the bank later terminates the loan due to breach of contract, you lose the house, and depending on the situation, you are left with a considerable amount of debt.

Regarding the "industry" - is, as far as I know, active in this field and has already written about it -> talk to the bank.

Before you get involved in such a game of hide and seek, you can't really enjoy life in the apartment, so look for an apartment in the size that you actually use. It will most likely be cheaper and without such clauses. You can tell that you have a guilty conscience about it, so better listen to your gut. Besides, tenants and vacation guests usually only bring work and/or trouble.

Someone from the industry here, by any chance?

Yes, there is someone I wouldn’t sign the contract in your place if you can’t fulfill it. We are, for example, extremely picky (with our commercial customers) or partly picky (in the private customer business). Therefore once again: talk to the bank before the cat is out of the bag. And if the clause is written as you stated in the contract, you won’t get a payment without a rental agreement at 95% of banks...

Someone from the industry here, by any chance

Yes, the nice gentleman has already replied to you. Edit: Too late