Financing / 10 or 15 years - maybe splitting makes sense?

hello, today we received a new financing offer: 20 years fixed interest rate, 2.38% effective - that fits us perfectly. now only the (nach)negotiation with the construction company has to go our way and then we are very close. possibly the new offer is also due to the ECB interest rate cut - in any case, it is significantly better than the last one (280,000 - equity 75,000, 205,0000 = 155,000 bank and 50,000 kfw).