For me, the only way to make the game nicely playable is to use this command in the console. Without it the mouse movement never feels right...

Using this setting makes the input handle similar in feel to the source version.

Other than that loving the update

I created a support ticket for this already. it'd be nice to get this as an official option in the menu.

P.s thanks so much for the free aim dead zone options!

https://docs.unrealengine.com/en-US/Platforms/LowLatencyFrameSyncing/index.html

To achieve the same input latency as pre-parallel rendering, it is necessary to synchronize the game thread to the RHI thread instead.
r.GTSyncType 1

Also this is only applicable if user has Vsync enabled. Disabling Vsync removes the need for messing with LowLatency mode entirely (i.e. such settings becomes irrelevant).

That's interesting, but I don't use v-sync, I shy away from any settings which create input latency.