make sure nothing is conflicting with it
also note that only Realism will have darker illumination, all other modes don't, all other stuff (speed, overlay amd raining blood should work globally

isnt doing anything

Indeed, the screen wobble is achieved by attaching a screenspace particle to the hand models.
This here is v4 with hands, so that might help, but I'm not sure?
That is indeed a very interesting note on ui_fx.pcf. perhaps exploitable in the future :)

but yeah, if I removed the invisible hands the screen warp didn't show, thats mainly why I went with v3 lol

I wanted the hands and rain + the screen wobble but after dissecting v4 for a while I noticed that (maybe?) the viewmodel is what makes the screen warp particle to spawn? BTW I found that you can delete all rain related systems in the particles file, rename the resulting pcf as ui_fx.pcf and enable said particle in the particles manifest (it's marked as deprecated at the end of the manifest), you can have both rain and the screen wobble

I'm surprised you went with overlay 3 rather than overlay 4 :o
An aggressive choice, I applaud you.