in the end I took a gordian knot or egg of columbus ish approach to it:
I can no longer make sense of the function that is responsible for firing
so I hacked in another one that is only called when you are sliding 💡
still some guns like the flamethrower doesn't work well in this way so I outright disabled them 😔
(so you cannot slide and shoot with the multitool primary, tripmine and the flamethrower primary fire)
the tnt also seemed useless during sliding .. but was amusing enough so it was left in 🤔
I added it as a new patch (just replace the exe as usual): ZortchBuild_1795.zip
please check if this is good enough and this is what you meant
it's probably not a good idea to add new features before release - but so far it seems to have not introduced any new bugs 🤔