I can highly recommend Bazzite for your needs. It has a KDE version which is clearly your favorite Desktop Environment (DE), it’s extremely safe/stable due to being an Atomic distro (you can always boot into the previous image if a system update broke something), has incredible documentation, supports almost any traditional app through Distrobox (VPN requires rpm-ostree for now), has a scripted easy install of Waydroid for native android emulation, and has a few tweaks preconfigured to ensure the desktop gaming experience is a little more seamless out of the box than a stock distro. It really seems to tick all the boxes for what you’re looking for.

If you want more focus on development and less on gaming, the Universal Blue team also makes Aurora for more developer-focused workloads, but Steam not being included in the image does introduce some usability regressions - Steam running via Flatpak or Distrobox is just plain less capable than a native install, though work is ongoing to make native installs Just Work even on Atomic systems.