Reading through this, we can see how this plugin differs from the 10 brushes script: this one apparently guesses which brush is a color smudge brush, which one is eraser and which one is a painting brush and automatically attaches those brushes (the last used ones from each category) to those slots.
I work with it. Two slots for any brush presets (pixel, smudge, deform or whatever) and one slot is any brush with force switching preset into the eraser mode. It memorize last used brush in certain keybinding slot.
Thanks @Rakurri again for the link to the excellent plugin. Without knowledge of programming it took near 10 minutes to grasp how to change number of slots more than 3. It gives me freedom similar to ClipStudioPaint brush-shortcutting.
Everyone can submit a plugin to the Resources page. It just need something called a KDE Identity, which is a login for a few other KDE platforms (like an old KDE forum).