Perfectly balanced star wars

Actually, there are 10,000 Jedi

It never really made sense to me how two sith and some clones killed so many jedi. At least in the old republic era, a jedi could easily kill tens of sith (unless they were weak, coming from a SW main)

The fact that there were many sith made it so that the power distribution of the dark side more spread out, making it so that even if they were a sith, they were basically powerless, the rule of two made it so that a sith actually had real power.

This isn't a zero sum game. You have people like Vitiate, Revan, and a large assortment of other powerful sith, and they were all ridiculously powerful. And then you have Vader and Palpatine, who, while powerful, are still only slightly more powerful/on equal footing with the people from back then.

The point is that there were a lot more sith than jedi

That just makes it easier for the sith to win.