Here in the Netherlands it's definitely not as crazy as in the US. People will fly the flag on national celebration days or on remembrance day. And during international soccer tournaments the country will turn orange. But the only flags I see on cars are upside-down ones from angry farmers protesting against environmental regulations and from nutjobs who still think that COVID vaccines contain microchips.
People do tend to fly provincial flags and municipality flags sometimes tho. Especially in the best province, Fryslân (I'm not biased at all).
Imo it's a good thing tho. Spreading our civilization across multiple planets is the only way to guarantee long long term success. Obviously we should also fix the climate change issue (and many others). But still, being spread across the solar system would give our species redundancy. An extinction event on earth like a large meteor strike would no longer be the end.