On Windows, Game Lags, Resource List Flickers, then game locks up

Sorry to tell you, but a Surface Pro 6 has only a 1.6GHz Quadcore. I dont know, what your Apple had before, but it seems it was more powerful.

Dont get confused by the 3.4GHz Boost advertised on the Surface. Its not worth at all. Intel Boost-Tech is only applied on 1 core, and then only for a few seconds. A Surface is not build to sustain boost clocks over a longer period and not at all cores at all.

Long story short: Its NOT at gaming machine at all.

Yes, your apps load much faster. Thats because the CPU can boost its clock more than double the base clock. But only for seconds. Thats enough to start a program. But a game needs that power over the whole gaming-time, not only at start. 

I would strongly suggest, to go back to the Mac for playing ONI. You wont have any fun at all with your Surface and this game. Its not build for such tasks.

If you bought it, because of the overwhelming 4,3GHz, try to get a refund, because thats not whats the machine can handle.

Further explanation: If you buy a used car, with say 100 horsepowers, and a nitro-boost, the car will have 200 horsepowers for a few seconds. But if the owner sells you this car with 200 horsepowers, its cleary a fraud. Same applies here. It your Surface was advertised (and sold) as a 4,3GHz CPU-machine, take it, and hit the vendor with it, as long as it takes to get your money back.