In 1642...1648, New Model Army achieved a total victory in Great Rebellion. From 1652 to 1660, no open defiance lasted long.
The Roundheads seized properties of their opponents - Cavaliers, Church and King. And were solvent till 1654.
But never broke even, despite years of trying.
In 1659, after rounds of retrenchment, it was estimated that Commonwealth had revenues of £ 1 800 000 per year - and expenditures of £ 2 200 000. Debt of £ 2 500 000, and adding £ 400 000 per year.
Of that, Ireland had revenues of £ 300 000 - and expenditures of £ 400 000, deficit £ 100 000. Scotland had revenues £ 150 000 and expenditures £ 300 000. Mostly military - despite repeated retrenchments, the military costs could not be decreased further without risking open rebellion and/or collapse of tax collection.
Commonwealth of England ended in a financial and political bankruptcy, despite a total military victory. The government of England is, and ought to be, by King, Lords and Commons.
And the Restoration did at least better in Ireland. In 1664, they could boast that they broke even and made a profit from Ireland - revenues £ 200 000, but expenditures mere £ 170 000 without an open rebellion.
Since 1689, England had been able to outtax and outspend everyone else.
But those taxes were voted by Parliament elected by English gentry.
Suppose France wins a total victory in 1779. The Armada of 1779 lands, and by 1780, French army holds Plymouth, Portsmouth, Rochester, London, Manchester, Glasgow... the Royal Navy has no shipyard in Britain and the remaining colonies and ships are hunted down in a few years, save those that choose to join the US allies of France.
What next?
How is the Excise Office going to work under French occupation? How much will the French occupation army cost?
Could even a total victory bankrupt Old Regime France the same way the OTL partial victory did?