The English Civil War ends in an incomplete and unstable Royalist victory, and the Stuarts must struggle & waste resources for a long time trying to impose a continental-styled absolute monarchy on their people. Perhaps Charles II openly converts to Catholicism earlier and/or James II holds on to pour more gas on the religious fires burning England up from within, as well. They intermarry heavily with the Bourbons and regularly invite French aid to reinforce their army & repress rebellions against their rule, reducing England to a de-facto French satellite over time and driving first religious dissidents like the Puritans, then political ones abroad by the tens or hundreds of thousands. 18th century England is thus still a relative backwater, suffering from a brain drain and dependent on France for its political survival and relevance, with a much more modest set of overseas colonies than IOTL.
Meanwhile the Dutch Republic avoids its Year of Disaster and the republican, de-centralist regime endures at the expense of the House of Orange. It soaks up many, if not most of the English emigrants, giving it an economic and intellectual boost when combined with Huguenots fleeing Louis XIV's repression in France, and with no Bank of England established to challenge the Netherlands' own banking mastery it replaces our England as the most consistent, commercially-minded and maritime-focused fixture of anti-French grand alliances in Europe. In wars with the French bloc, the Dutch inevitably poach of many of England's New World colonies as they had once done to the Portuguese back when the latter were in union with Spain, often with the enthusiastic support of the colonists themselves outside of adamantly Cavalier Virginia and Catholic-settled Maryland. The 18th century Netherlands stands out as pretty much the only non-absolutist regime left standing in Western Europe.
Of course, just because they aren't absolutists doesn't mean the government in The Hague doesn't ever think about centralizing more power into its own hands and trying to extract more from its new colonies than they care to give. Perhaps they might even push the envelope hard enough to find themselves staring down rebellions in New England and New Netherland, motivated not so much by memories of traditional English liberty (although that's almost certainly going to be a factor for the former at least) but by their belief that the regime back in the mother country has betrayed
the concept of 'True Freedom'. The English and French might well aid these rebels however they can, despite the obvious bad blood, just to spite the Dutch vultures who have chipped away at their colonial empires for so long.
But no matter - even if they lose here, the Dutch Empire will still grow and grow, spreading across Africa from the Cape and across Asia from the East Indies, later retaking Taiwan from China in addition to securing a growing number of territorial concessions on the Chinese mainland. Eventually, they will become the world's largest empire and professed defenders of a constitutional, liberal order standing against the absolute monarchs and more radical types dominant across the rest of Europe (perhaps even reconciling with rebellious New Netherland) by the end of the 19th century...
