Part-time "small business owner" impact on the loan?

If that is the case, the bank will come to the same conclusion. First, stay calm, they just want to check initially. It's just a matter of categorizing.

Even if I don't list that under my income?

The documents usually to be submitted include income tax assessments, even for applicants who are employees. All types of income are visible there, i.e. lies won't get you far here.

It is what it is now anyway. It's not impossible, it will just take longer, require more documents, and some will reject it.

I was also asked about this at Volksbank and I said the same as here in the forum. They also refrained from including anything under income. I received a financing confirmation from Volksbank.

The part-time self-employment has only existed since 01.12.2016.

It’s me too, freelance self-employed.
In the 4th year it was considered hobby activity for tax purposes. No longer worth mentioning. In that respect, I do collect my invoices and receipts, but no one is interested.
You also don’t slide into the auditable self-employment category for a bank or the like, since you are employed full-time and receive a salary.
Could it be that you have overstated your income somewhat to the bank to boost it? Retract this information with the bank.
A side job that does not bring in regular income, done occasionally for fun and hobby to have a few extra euros for vacation, may be of annual interest to the tax office, but otherwise is not really worth mentioning.

It's me too, self-employed freelance.
In the 4th year it was hobby loss for tax purposes. Not worth mentioning anymore. So I do collect my invoices and receipts, but no one cares.
You don't slide into the auditable self-employment lane for a bank or the like, since you are employed full-time and receive a salary.
Could it be that you bit off more than you could chew to inflate your income towards the bank? Retract this info from the bank.
A side job that does not bring in regular income, which one does out of fun and hobby to have a few more euros for vacation, may be interesting to the tax office annually, but otherwise not really worth mentioning.

Hello,

as I said, I did not include the income from my small self-employment in my household budget. There I only calculate with my fixed income from the employed position.

The MHB has at least requested the income surplus statement and is now reviewing the whole thing.

Yes, but something must have been reported to the bank.
I don't know this bank, is that the reason?
With us, no bank wanted to see our tax return, only 3 salary statements. Done.
The small business issue is not worth mentioning, as already said. There is nothing to review!