At first it is rather confusing how to make the virtual keyboard open after installing it and enabling it in the KCM. That is so because it's hidden in the system tray among many other items by default. The user needs to pay particular attention when opening the tray to notice there is an additional tray icon for virtual keyboards, or already know it's there. It is not particularly discoverable. IMO the virtual keyboard icon should either be always visible once a virtual keyboard is found or be set to be visible once the user enters tablet mode. This makes the icon discoverable and easy to touch/toggle, and might even additionally serve as a tablet mode indicator.
*** Bug 440570 has been marked as a duplicate of this bug. ***
As far as I can tell this has been resolved with https://invent.kde.org/plasma/plasma-workspace/-/commit/7e2531f33df8ebaf80a1b5ad11ea143c629dfbc1 . Can you confirm?
Pretty much.