You are completely right. With the Oculus link, Facebook really made the Rift S redundant.
One minor point in favour of the Rift S though is that it is more comfortable. The Quest is really heavy due to being an all in one.
I have used the quest and I don't find the SDE particularly jarring. Mind you, I still use a rift at home.
In what way? Link don´t remove the pentile OLED panels on the Quest. Rift S also have an extra camera so it tracks a bit better. Optics is still the same. Overall design is still the same. If you want wireless you go quest. If you have absolutely no need for wireless I would go rift S as the halo don´t interferr with my headphones luckily. Stock audio on Rift S is absolutely horrible
As for Vive cosmos sadly I haven´t heard that good but now that they dropped prices who knows and hopefully that have revised it just like the hp reverb is revised. You do have a chance to get better hand controls and tracking with the light houses the one that came with reverb is not up to par with the oculus touch controllers.
But for racing that is not something you really need I had no problem with drifting or the reverbs headtracking while sitting.