What if the Dutch got back all there pre-1795 colony’s after the Napoleonic Wars?

In OTL, the Dutch lost the Cape Colony, Ceylon, some cities in India and some land around Suriname (Guyana). But what if in an alternate timeline, they got back all these colony’s.

What are the effects from this on the Congress of Vienna, United Kingdom of the Netherlands, Belgian Revolution, Scramble for Africa, Europe in the 19th century and, eventually the 20th century, although that last that is too complicated maybe.