@robswfc - You can decide at what fps you are happy to constantly run at or have high fps that constantly drop.
Most people want max fps whilst I want smooth constant fps and that's why I run at 30fps 2xMSAA 3840x1024 with my old hardware.
NOTE 3A/3B is what I suggested you look at, but here is what i'd try.
I assume your NPI vsync settings are 'app control' and that you haven't forced any settings there.
Your 144Hz monitor - config.cfg:
uset r_mode_refresh "144"
uset r_vsync "3"
That will give a constant 48fps if it can.
uset r_mode_refresh "144"
uset r_vsync "4"
That will give a constant 36fps if it can.
uset r_mode_refresh "120" - if your monitor can run at 120Hz
uset r_vsync "3"
That will give a constant 40fps if it can.
As an example, BenganJ had a gtx1660ti and set all his extreme settings from his first post and 4xMSAA and locked at 30fps because his gpu on his 60Hz monitor couldn't keep 60fps.
uset r_mode_refresh "60"
uset r_vsync "2"
That will give a constant 30fps if it can.
An another option would be to use 'tear control' to turn off vsync when the fps drop below it. This way it'll only drop the fps it needs to rather than drop to the next vsync level... but you will see screen tearing when vsync is off.
Using one of the above config settings and then do these:
In NPI set Vertical Sync to 'app control'.
In NPI set Vertical Sync Tear Control to 'Adaptive'.
Or, if your monitor is gsync/freesync then look here:
viewtopic.php?p=46155#p46155
EDIT: Just in case you don't know why you have fps drops.
Your cpu generates each frame.
Your gpu renders each frame.
If your fps drop and gpu usage is 100% then your gfx settings are too high bottlenecking your gpu.
If your fps drop and gpu usage also drops then your cpu is too busy running the game etc or current frames are more detailed which takes your cpu longer to generate, your cpu is the bottleneck as it can't meet the demand which is why your gpu usage drops.