Changing Mouse ButtonRebinds for ExtraButtons programmatically - kcminputrc

Hello everyone, first post.

I’m looking for a way to programmatically change the ButtonRebinds for ExtraButtons on the Mouse, to apply different binds depending on which application I’m using.

So far I found that when setting the ButtonRebinds up through the system-settings gui, they end up in file ~/.config/kcminputrc

Now I’ve seen this post about flipping the leftHanded property of the mouse through a busctl call, like so:
busctl --user set-property org.kde.KWin /org/kde/KWin/InputDevice/event5 org.kde.KWin.InputDevice leftHanded b true

So I’m guessing something similar can be done with the ButtonRebinds property, but it doesn’t seem to be linked to a specific [libinput] mouse entry in kcminputrc as it appears a the very top of the file, like so:
[ButtonRebinds][Mouse]
ExtraButton1=Key,Control
ExtraButton2=Key,Shift

If this would work via busctl I suppose the command to achieve this would look quite different.
If not, I’m ok to edit the file directly and have the system reload the config one way or another, preferably not through a logout/re-login though

Could someone please point me in the right direction ?
Thanks!