Hello KDE community,
I have been looking through configuration options for quite some time, yet it seems I cannot find the proper setting to turn it off.

I am having the following problem: Sometimes if I swipe over my trackpad of my Xiaomi Mibook, it opens an "overview" mode. It shows me all active windows/applications from all my workspaces. This is really frustrating when soley using the trackpad. - How do I disable this?

Running Debian Stable 9 (Stretch), so an older version of KDE.

If there is demand I can upload a picutre of said feature. (Unfortunately I could not printscreen, so its an actual picture off my phone...)

The picture would be appreciated.

I suspect you may be triggering a hot-corner effect by pushing the mouse into the top-left corner. You can configure those in System Settings -> Desktop Behavior -> Screen Edges.