KaOS is an independent Linux distribution using the KDE Desktop and includes the Calligra office suite and other popular software applications.
The idea behind KaOS is to create a tightly integrated rolling and transparent distribution for the modern desktop, build from scratch with a particular focus. Focus on one DE (KDE Plasma), one toolkit (Qt), one architecture (x86_64), plus a focus on evaluating and selecting the most suitable tools and applications.
All work is geared toward packaging, not developing new tools or applications. There is no goal to make the possible software available. KaOS will stay limited in the repositories' size and will work on quality instead of quantity. That goal makes it clear; a large user base is not what is intended or expected.
KaOS targets users who have tried many Operating Systems/Distributions/Desktop Environments and have found they prefer a Distribution that uses all its available resources to work on one DE to make that the best possible know that after their searches, the best for them is KDE Plasma.
Similar: The 12 Best Linux Distributions for Windows Users