while we're on the topic, what do you guys think will happen with France in the future of ittl? Calling in experts @Basileus_Komnenos,
Honestly the main lynchpin regarding the various revolutions that occurred in the 19th and 20th Century was caused largely by economic circumstances. A major contributor to the July Revolution in 1830 in otl was the French economic policy. The Bourbons did see France begin its industrialization, but also implemented some questionable economic measures. Britain entered into a period of economic prosperity thanks to the victory from the Napoleonic Wars leaving it with naval pre-eminence and more vast colonial empire. This along with industrialization led to more British goods flooding into European, and thus French markets.
The Royal government alarmed by this tried to set tariffs to stimulate consumption of domestic goods. The problem was that there was neither enough supply, nor as good quality French goods available to sate domestic demand. This created a shortage of goods which led to price increases. Many people petitioned the King to lower if not remove the tariffs he imposed, but he refused remembering how that exact same thing led to his eldest brother losing his head. He learned the wrong lessons from Louis XVI. This was fundamentally the problem with many states within the political framework established at the Congress of Vienna. The counterrevolution was not effective in the long-run as it did very little to address the socio-economic conditions that led to these revolutions in the first place.
Prussia was able to hold back on having a Constitution until 1849 until major crop failure's and economic issues led to people turning to Revolutionary ideas. The Russian Empire with its large military and iron-willed Tsars were able to get around this by using brute force to suppress any revolutionary movement, but they kicked the can down the road for so long that minor problems which could have been fixed relatively easily snowballed into the violent Revolutions that saw the monarchy abolished and the Romanovs executed.
This was a major problem for the Papal states which was so horribly administered that the Conservative and Reactionary Metternich all but washed his hands of the whole affair with him later remarking that the Papacy's restoration at the COV being a less than ideal solution.
Most of the absolutist Kings probably could have kept their throne and powers had they not been so scared and traumatized (in the case of the Bourbons/Habsburgs) of "dangerous" revolutionary ideas that they shied away from things popularized during the Enlightenment in favor of preserving the status-quo at all cost. Things like the modern French administrative system of Departments, was actually something which had its roots as far back as Louis XV. Though he was unable to make much meaningful reforms due to his ineptitude and because of opposition from the nobility.
A major contributor to this rabid fear of Revolution was, in my opinion, Napoleon's return to France which scared the daylights out of the Europe throwing cold water upon their sense of security that the Revolution had been crushed. I don't think your tl has Napoleon returning from Elba which should be somewhat of a good thing for the rest of Europe as this means that the other states would be more open to ideas of economic/administrative reform which would largely blunt support that Revolutionaries would receive. People are largely concerned with having a roof over their head and food to eat. If these needs are met, they'd feel content with the current political system. As such most major uprisings which led to large scale revolutionary movements would probably end up being lesser demonstrations which would largely fizzle out without much popular support.
This was kind of what happened during the 1848 Hungarian Revolution as the Imperial forces eventually regrouped for a counteroffensive. Plus Hungary's population was quite divided as there were many still loyal to the Habsburgs (keep in mind that under the reign of Franz I Hungary supported him against Napoleon to the hilt being one of the most loyal regions) and many ethnic minorities who did not like the idea of Magyarization pushed by Hungarian nationalists who were funded by Hungary's nobles. The Habsburgs in otl missed a large opportunity to snuff out the rebellion for good. Franz-Joseph should have cracked down hard upon the nobles who were disloyal. If he later engaged in land redistribution (sort of like how Napoleon did in Naples) he'd earn the support of the peasantry.
With less of a fear of revolution and more openness to reform, it also means that unlike otl, the idea of absolute monarchies and nobility are much more entrenched and mainstream.
Plus even with Constitutions, the transition to what would be the modern "Constitutional" arrangement where the government became essentially a "Crowned Republic" was quite a long and arduous process caused by many unique circumstances. King Louis XVIII of France was shrewd enough to use the Constitution to augment his own power to something arguably greater than what the French monarchs had during Louis XV and Louis XVI where the nobility stymied him. Parliament was quite deferential to the King here and Charles compromised a bit which caused him to fail upward increasing his own popularity among the people. In the long-term its likely that Henri V who actually grows up in France would be skilled enough at following in the footsteps of his grand-uncle to maintain the throne's position. King Wilem I of the Netherlands managed to be quite effective in this. However where he managed to be quite good economically speaking, his blunders in social policy like how he pissed off both Catholics and Protestants led to the Belgian revolution.
Here's a meme about Charles X I made which I forgot to post when you released that chapter about him.