We've been largely winning against the sea since 1500, and that's with windmills and wheelbarrels of mud. Look up the Afsluitdijk. Or the Deltawerken. Our combined 'water defense works' are considered one of the modern wonders of the world. The Dutch will never surrender to the sea. Even if the rest of the globe will experience some catastrophic flood, the Dutch will figure out how to stave it off.
Actually, much of the Netherlands is already "literally underwater", and most of it would be flooded by storm surges. It's just that there's a highly layered defense of dikes, dams and pumping stations. Next time in Amsterdam, check out the display at city hall.
Since the disastrous 1953 flood, they've installed humongous valves at the mouths of all estuaries (Delta Works). If sea level increases more than a meter or so, they'll need to modify it.
As already noted in other sibling comments, the Netherlands is famous for having lots of territory under current sea level. According to Wikipedia, roughly half of its territory is 1 meter above sea level or lower. Two more facts from the same source: it is one of the more densely populated countries in the world, and the second exporter of agricultural products (only behing USA).
On the positive side, they have 500 years of experience building dykes and defending their coast line. Their experience will be invaluable to fight off raise of sea level during the current century, inland and around the world.
On the negative, they have huge liabilities that can be triggered even by temporary floods. Refugee crisises during storms, lost of high value agricultural land due to increased salinity of soil, etc. All this will cut down on their budget to support their current dyke infrastructure, precisely at a time when they should be extending and enhancing it agressively.
Rinse and repeat for 50 years, and you are bonded to see an ever growing number of marginal areas that are deemed not worth salvaging and left to be turned in unproductive swamps. I do not see the impoverished and overpopulated remanant of Netherlands surviving for long afterwards.
Best case scenario I imagine is they will be absorbed by Germany, who may at that time have the economic power to keep the dykes in running order. Or they may try to stick to their own guns, in which case it is hard to tell how much land they will be able to hold dry.