Financing monthly installment €2500 with 40 years term

Ask your disability insurance what your surrender value is and compare it with your payments.

Off-topic, but if your disability insurance really has a surrender value, then you don’t have a pure disability insurance but a combination product of disability insurance and a savings contract!
A pure disability insurance uses the contributions solely for the risk of disability and nothing else. Exactly the same game as with alleged risk life insurances, which ultimately perform a "premium refund." Here, too, in addition to the actual risk life insurance, there is another linked savings contract.

After 20 years of Riester, Rürup, equity funds and tens of thousands of wasted hours with financial advisors, I have to say: All rubbish

I can well understand the frustration. But nowadays, thanks to the internet, there is more transparency in the market and you have to trust a shady financial advisor less. My somewhat bolder claim is that with Excel and the like, it is easier to recalculate and compare things. The same applies to retirement as to real estate financing: if you haven't understood the product (building savings contract etc.), then it is most likely the wrong product.

Therefore, I recommend reputable fee-based advisors for financial consultants.

Now comes the next hype with ETFs. Sure, you can make money from it, but only if you manage to convince others that this is the next big THING and they finance your profit.

Although that is hardly the case with ETFs. No front-end load, no commissions, expense ratios ~0.2%. And that is very cheap considering that you basically buy the entire asset class. There is a reason why all the representatives do not recommend it. As for Riester, Rürup and the like... yes, the problem is that there still has to be an apparatus fed. The money naturally comes out of your own return, and if you then have a high proportion of fixed income (guarantee...), then nothing is left.