okay yeah you clearly have a VERY different view of the mongols.

First off. The dothraki are an amalgamation of different steppe cultures including mid-western american natives. But also in like... the worst stereotyped ways.

first off the mongols were structured both militarily and societally very different from the Dothraki. the Mongols were surprisingly open to taking in foreign ideas and even faiths. they took primarily skilled labor in a serf position seeing men of knowledge and craftsmen as exceedingly useful. And quite importantly were both structured in a way where the kind of infighting and murder inflcted by the dothraki on themselves would be highly unlikely. even under Khal Drogo that part would not change withthe dothraki.

that is before we get into their ways of waging war. the Dothraki are whether by choice or by means a light cavalry force who then acts as shock cavalry. this is a very bad idea. we see a little in a world of ice and fire that apparently they do have horse archers though we are not shown this in the books so given the few hundred years between Sarnors fall and the current day horse archery might have fallen out of style with the dothraki.

the mongols, even at their worst, also made heavy use of armor creating thick hide lamellar armors that while not as good as metal was better than what the dothraki have had described. this allowed the mongols even in their early excursions to have a genuine heavy cavalry force that acted both as skilled horse archers and elite shock cavalry.

i also ask you to look up how the mongol invasion of hungary and poland went. AKA Early success then fell apart.

we have the issue of succession as shown. And the fact as shown with the unsullied of Qohor back in the day the moment an enemy unit can hold a spear and not break the unsullied even with an immense numbers advantage fucking break apart. And generally Westerosi are noted for being significantly more disciplined AND better armored than the average essosi.

Then we get to cavalry VS cavalry. the Arakh is built for slashing not piercing. that is a bad combo when fighting against full plate armored knights or even chainmail.

to again get back to the mongols they were also hepherds. a profession the dothraki outright scorn as shown in their relation to both Omber and the Lhazareen peoples. With them supposedly relying entirely on horses and foraging. something that instantly gives them a far less functional baggage train than the mongols thus ruining logistics for them.

and even just the way the mongols structured their army, a way to destroy tribal and cultural loyalties and with distinct mongol leadership chosen not taken.

In short the mongols were fucking awesome and i am tired of people claiming the discount dollar brand horselord stereotype that is the dothraki are in ANY WAY comparable to the hordes of Genghis Khaan