How and why did the Algerians lose the Franco - Algerian wars from 1681 to 1688 to the French and lose tens of thousands of their soldiers and civilians to the French while the French suffered no fatalities and no casualties to the Algerians?

You mean the 1800s thing probably; Algeria was firmly under the Turakas back in the 1600s.

Now the Firangs did suffer a few casualties but on the whole, OP is mostly right.

The French conquest of Algeria is actually a pretty standard example of how European colonialization used to go around. The prevailing powers had been in decline since the early 18th Century because climatic change had impacted warmer climes far more than cooler ones- sparking off rebellions and increasing decentralisation. Europeans had far more standardized systems in contrast to the Algerians whose crack troops used roughly equivalent tech but were far fewer in number for this reason. And the Europeans had Nationalism- the greatest religion of the Modern Age.

And of course, let's not forget the driving impulse of the 19th Century Firang state- to regain the Superpower Status it'd possessed before the Angrej, Rus, and Almana shanked their Emperor Napoleon.

1871 was what happened when they really went all out but in the 1830s, the Algerians were no Prussians. When the French landed 35K men, all the Bey- a Turki “vassal”- had around 9K real troops, nearly all Janissaries who hated him, and a bunch of part-time ghazis and pirates. On paper, he had equivalent troops. IRL all he had were huge bills and disgruntled Amirs.

After a round of roughly inconclusive battles, the Janissaries left and the incompetent part-timers, militia, and pirates melted in the face of the Firangs. The Bey, still getting hate from Amirs- many of whom were openly talking of how glorious Firang systems were, chose Surrender and Exile in Romaka rather than return to Kanstaniya and risk his neck. Everyone's happy- the militia, the Bey, the Amirs, the locals.

Until the Firangs started massacring the Locals, hanging Amirs and Merchants and Ulemas and basically anyone they didn't like the look of without trial, looting everything they saw, and basically enslaving the entire Country.

But that's another story and I suspect won't get me many upvotes…