The icon is being shown on the system tray right now. For starters the green on gray is a bit hard to see and overall it's hard to see the different icon when the Enable/Disable Virtual Keyboard action is triggered.
For this, we probably want to use the standard style where the "on" version is just the normal icon, and the "off" version is that icon with a red line through it.
How about fading it? Much like we do when there's no wifi, AFAIR.
A possibly relevant merge request was started @ https://invent.kde.org/frameworks/breeze-icons/-/merge_requests/168
Git commit 8faf94f044c5859911dc5734c615d69c44711e68 by Andreas Kainz. Committed on 14/11/2021 at 20:50. Pushed by andreask into branch 'master'. M +13 -14 icons-dark/status/22/input-keyboard-virtual-off.svg M +14 -15 icons/status/22/input-keyboard-virtual-off.svg https://invent.kde.org/frameworks/breeze-icons/commit/8faf94f044c5859911dc5734c615d69c44711e68