Captain_Cretin I've used 'Leatrix Latency Fix' a while ago and I don't think it does anything that special I think it's just the TCP ACK delay change, perhaps a few other tweaks ? I'm sure it might help if your game uses TCP but most games use UDP.
There's lots of tweaks for game networking and I've most likely tried them all, I'd certainly start with your network card settings and change your interrupt moderation to disabled, that makes a big difference, perhaps not with ping but with game responsiveness. In fact a lot of NIC offloading / default NIC settings need changing for gaming such as LSO etc. Indeed many tweaks won't as you say have a major effect on ping but will have an effect how fast you push packets out or in or how fast they get processed by the game. Have you tried TCP optimizer ? that's another 'goto' starting point with tweaking.
www.speedguide.net
Also major places to tweak in the registry are below, certainly AFD (Ancillary Function Driver) is a place where buffering happens and I've made significant changes here.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AFD\Parameters
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
As always though tweaking the registry values can have a detrimental effect if you're not careful.
Setting QoS / tagging packets in and out with a DSCP value of 46 can improve things as well, in effect making your packets look like a VOIP call i.e. Windows group policy editor and router changes for QoS.
Other practical things such as disabling Windows 10 updates, disabling not needed services like all the xbox junk, windows search etc. try 'windows 10 shutup', another good tool for helping, The whole tweaking scene is massive with lots to consider and try, even your anti Virus provider and settings can have a detrimental effect on gaming, I could probably write a book on tweaking