One statistic that always lingers in my mind on this topic is that, IOTL from 1780 to 1810, more African Slaves were imported to the United States than in the
previous 160 years combined. That's with the U.S. banning the trade nationally in 1808 and with several Southern States, including South Carolina, instituting State-level restrictions even before 1808. Cotton alone doesn't explain this either; As late as 1800 only about 11 percent of all slaves lived on cotton plantations. Slave labor was being used in the production in everything from tobacco, to rice, to sugar and finally to cereal crops like corn and wheat on a profitable basis.
IOTL, the (mostly) shutting off of the Trans-Atlantic Slave Trade in 1808 is probably the only thing that prevented Slavery from becoming established in the Midwest and possibly much of the Mid-Atlantic. Here, it probably does given the Crown and the British Government at large has a financial incentive to keep the flow open for longer.
Presuming the French don't get into any other foreign adventures,
I'm inclined to think it's at the least delayed and doesn't go as radical as it did IOTL:
French involvement in the Seven Years’ War and the American War of Independence added substantially to the state’s debts. Jacques Necker, finance minister from 1777 and 1781, had largely funded France’s war effort through loans. As a result the state debt ballooned to between 8 and 12 billion livres by 1789. Serving that debt consumed an increasing share of state revenue. Moreover, worries over France’s creditworthiness meant loans could only be acquired at higher rates of interest.
Fiscal and diplomatic problems came together in 1787. The international prestige of the monarchy was undermined when it was unable to intervene in the conflict between republican and Orangist forces in the neighbouring United Provinces because of a lack of funds.
The French involvement in the American War of Independence had an impact beyond the financial. The American rebels had fought under the slogan of ‘no taxation without representation’. Yet the French officers and soldiers did not enjoy the same political rights that their American allies were fighting for. The incongruity of an absolute monarchy fighting in defence of a republic founded on universal male suffrage (excluding slaves) was not lost on many commentators in France and Europe. The Marquis de Lafayette, who had served alongside George Washington, became a hero on both sides of the Atlantic. The Declaration of Independence provided inspiration to would-be reformers and revolutionaries in France. Indeed, the Declaration of Independence would provide a template for the Declaration of the Rights of Man and of the Citizen in 1789.
With that said, there's always the chance for the Monarchy to still shoot itself in the foot by getting involved in the
War of the Bavarian Succession. I've also read, over at the other place so take it with a grain of salt, that French scouts were at work in Egypt and the Levant, laying the framework for future operations there against the Ottomans.