Longer mortgage for more life flexibility? Need help.

I’m currently at a point where I’m buying a new-build house, and for that I’ll need to take out a loan of around 170,000€. I’m planning to take it over 20 years, which would be roughly a 1,000€ monthly payment. Split between two people, that doesn’t feel like such a huge burden. But now I’ve reached a point where I’ve started thinking a bit more seriously about life and future needs. We have 3 large dogs. Right now I drive a 2016 Golf 7 Variant. I’m aware that I’ll probably need a bigger car or