I find this to be a fairly basic setting, which is required in a lot of cases, especially on Linux (for example, on many Matebooks on Linux, for some reason, trackpad scrolling is overly sensitive). The setting has been present in KDE for as long as I can remember; it’s very basic and just seems like something that should be there. Right now, the only way to tweak scroll speed is through the command line, which is not optimal. I have found multiple merge requests over the years trying to add this feature to GNOME and multiple discussions on the topic, but it’s still not entirely clear to me why the feature has not yet been implemented.
P.S. I am not a developer, and I am not demanding anything. I am already happy to have the opportunity to use a desktop environment as good as GNOME for free, and I am thankful to all the people contributing. I am mostly just wondering why such a basic feature was not implemented.