Thanks for starting this topic Valorie.
Hoping I do not repeat similar observations, wanted to share one thing.
Background
As soon as KDE application(s) are not publicly tied to "KDE" desktop on several levels, fair rules of competition become possible. I have learned this through the history of KEXI since 2002: in years where we had strong Windows support were extraordinary regarding user feedback. The same about caring for non-Plasma desktops compatibility. "Plasma users" tend to be a minority target at least for specialized apps by definition, well that group is a minority on the Desktop itself, so how it can be otherwise? And numbers further decreased after the decline of some desktops towards touch based UIs.
Boud can correct me here but Krita loks like a very good example too. As soon as an app project is known as a normal standalone app, things start to be normal. For some reasons not caused by us, KDE folks, this is not *default* state for apps. "For KDE only" has been long the default. For Qt-only app projects it is a bit easier. It's good when we attract these projects under the KDE umbrella.
To compare with above examples, Calligra as a whole has not managed so far to escape the "Office suite for KDE" or older "Integrated KDE office suite" unfortunate stamps.[1][2] Well, I bet such sentences still sit in package descriptions across some distributions. Here, again even in KDE circles the #1 FOSS competing office suite is perceived as global instead of Calligra. I've not seen too much of spontaneous use of Calligra during Akademy presentations.
We were close to being global in the gold Nokia and KO GmbH times (2009+) even if there was some more interest in mobile targets.
And now:
One challenge for the integration I would see it that "part of the KDE community" needs to be in conflict with the "go global". Application contributors need not to worry that their attempt to "go global" is not the preferred choice within the KDE family.
[1] I do not see this much different from Microsofts' behavior of promoting apps "running best on its operating system".
[2] Just unfortunate messaging since at technology level we have no such problems. We stay on top of extremely portable Qt, CMake and KF5 technologies, paired with great multi-OS KDE CI infra. As it's worth mentioning the KF5 prject realizes its road to "global" just very well IMO.