I think so too. Equity should then be around 150k. That should work. If you really have secure jobs... why not. But for me, it would also be too much... But actually, our 500k are too much for me as well. However, I don't have a secure job.
With a construction volume of about 800k, 40k buffer is not that much. You should plan enough money for exterior etc. And a multi-month salary reserve is also not wrong. We have about 20k construction buffer + 70k for exterior, climate control, kitchen, moving, alarm, furniture, etc. In addition, a reserve for 1-2 years in case something goes wrong (as I said... I don't have a secure job).
Best regards, Steffen