Looking for a app-launcher which play nicelly with Karousel

I'm coming with a question rather than a bug. Scroll-Tiling WM is revolutionary, so ergonomic, and so easy to use. Unfortunately, all desktop environments consider the app launcher (a.k.a. menu/drawer) as a floating window, which is not perceived by STWMs now.
I use Karousel on an ultrawide display, which made me think: opening an app launcher behind the currently active window would be so nice and straightforward! I would not move my cursor across a vast screen only to launch a new window. Even better: the launcher spawn in place of the new window will be opened (by this launcher).
I am considering multiple solutions:

• Finding such an existing plasmoid that can act like a normal window (after the transition to Plasma6 aren't so many now),
• Using a third-party launcher (maybe rofi?, but rofi also by design creates floating windows and doesn't have features I generally need),
• Fork an existing plasmoid (potentially TilingMenu), making it windowable (but my coding skills are rather poor).
  What do You think guys?
  Thx

This issue is a discussion about making an app launcher work as a normal Karousel window, but it names no files, tests, or implementation entry point. First clarify whether the goal is an existing Plasma launcher, a third-party launcher, or a Karousel-related change; done is not defined until one concrete approach and its expected window behavior are agreed.