@bcrescimanno It looks like there has been a pending PR for over 3 years implementing the feature in mutter, and it has been discussed 2days ago (@jadahl do you have more info about this ?)
The implementation looks solid and has conveniently the same setting name as the one i created, i only have to make another one for the mouse scroll speed.
edit: it looks like there is also a PR for adding the settings in the gnome settings
and in the schemas:
Might have just wasted my time, lesson learned: check the 3yr old PRs ^^’