Building a house now or in 3 years / interest rate development

So we had 2750 euros net back then, of which 2600 came from my husband (different every month, we took the lowest amount) and 150 euros pension from me. With that we took out 210,000 euros and financed 100%. It was possible and we could have gotten more (we initially wanted to build), but with the follow-up financing after 5 years they looked more closely. The tightened credit guidelines already applied here, which have apparently been relaxed again by now. Anyway, I thought the installment of 650 euros was okay, but I couldn't or wouldn't imagine more. I had always wanted a house, but not for an installment of 1200 euros or more on such an income (= nothing from me). And we have and wanted no children... Meanwhile, I also work, so things look quite relaxed. But still, you want to be done with the loan at some point. How is that supposed to work with even less income and twice as high a loan amount? It was already said here including incidental costs at 1700 euros. That leaves 500 for living? And that only if the construction costs don’t go beyond the budget.