Absolute monarchy: how to not have a revolution every 10 years?

[Monsieur Alphonse]

There's absolutely no reason to have more than one school in any one province, and no more than 4 schools total. You will finish the tech tree way way before your game is over.

It is unbelieably easy to avoid revolutions by just having 1-2 units in a region capital, even without pleasure palaces or churches, with a popularity of about 70%.

That is correct. Build a school and a pleasure palace in four regions and you should have no problem. Or let a revolution happen and build one pleasure palace and four schools in one region.