I hope September ISO will be the best KDE distro that is out there. If you don't mind, I have a great idea how to beat the hell out of Manjaro KDE and surpass them on distrowatch. As a maintainer of a few boxes, I have experience with maintaining them and improving speed, reliability and visuals that people envy (!).
I. Improve responsiveness and speed of KaOS by applying Linaro patches to the kernel, or create udev rules for the system to use appropriate I/O scheduler depending on the type of hard drive: BFQ for spinning drives, mq-deadline for SSDs.
Real life experiences:
a) Manjaro uses Linaro patches and uses original Linaro BFQ scheduler. Mainline kernel (starting from 5.2.x) uses BFQ-mq (using confusingly BFQ name for BFQ-mq😉.
b) My Arch box with openRC (old computer) uses udev rules I created and the results are amazing.
c) The big daddy of distros- Fedora uses mq-deadline. By my tests GIMP starts significantly faster.
I have never experienced any trouble with BFQ or udev rules or Linaro patched kernel. Its extremely robust and is adequate for September release. The I/O scheduler was always a bottleneck in Linux. Now we have reliable and tested solution. Just apply the either solution.
Scientific proof by Italian professor:
https://www.youtube.com/watch?v=l7j1AqTZKG4
II. Improve greatly fonts to surpass anything that is currently available by any distro including Ubuntu (!).
Please let me explain how I did achieve it on the aforementioned Arch box:
1. $ xrdb -query | grep Xft
--> should be: antialias: true, autohint: false, dpi: 96, hinting: true, hintstyle: hintslight, lcdfilter: lcddefault, rgba: rgb
2. $ cat /etc/X11/xinit/xinitrc.d/xft-settings.sh
--> should be: antialias: 1, autohint: 0, dpi: 96, hinting: 1, hintstyle: hintslight, lcdfilter: lcddefault, rgba: rgb
$ echo "$XFT_SETTINGS" | xrdb -merge > /dev/null 2>&1
3. Just to be sure in home folder create a "dotfile":
$ cat .Xresources ---> all Xft.dpi/antialias/hinting/hintstyle.... as above
4. Now for the fun part, you need 3 packages and appropriate setting (without seettings in WILL NOT WORK!):
$ git clone https://github.com/pdeljanov
/infinality-remix.git
-----------------------------------------------
$ cd infinality-remix/freetype2-infinality-
remix
$ makepkg -sci
===============================
$ cd ../fontconfig-infinality-remix
$ makepkg -sci
----------------------------------------------------
$cd ../cairo-infinality-remix
$ makepkg -sci
Set it exactly like this:
Location of settings: /etc/X11/xinit/xinitrc.d/infinality-settings.sh

https://pasteboard.co/IpiJykc.png
If you do not set it EXACTLY like this all will be for nothing.
In order to achieve the best results with fonts pleas adjust your dpi (accordingly to your screen- everyone has different!).
III. 1. Set up a theme "breeze dark" --> dark panel and windows decorations + breeze (light) for the rest and clean up anything from the desktop.

https://pasteboard.co/IpilJ5A.png
https://pasteboard.co/IvRAiCC.png
2. Unlock panel, click on the desktop and change from "desktop folder" to "desktop" - it should clean the desktop.
3. Put the panel on the bottom (default, don't change)
4. Use default (don't change, application switching)
5. Change clock to 24hrs by default
6. Right click on the panel and use "show only apps from the current desktop" (old work-spaces paradigm, so new desktop/workspace is empty).
7. Do not add any bookmarks to Firefox. People hate this when Firefox starts with "the crap" [they want their youtubes and facebooks!! - yeah I know!]. The user decides their bookmarks. Firefox starts with nothing: empty tab.
IV. To fully utilize KDE capabilities pleas install whole KDE suite including KDE PiM. Its more powerfull and suits much better KaOS philosophy of using KDE and qt. Thunderberd is for kids. KDE PiM has very powerfull email client KMail. Its a beast.
PS. Just for fun (for you to envy!):
https://pasteboard.co/IpizzkS.png
https://pasteboard.co/IpizW5b.png
https://pasteboard.co/IpilJ5A.png
https://pasteboard.co/IpixccR.png
https://pasteboard.co/Ipiy2JP.png
https://pasteboard.co/IpiyvU1.png