You are heavily overestimating how much effort is required to develop a text editor. It's a single person project using components that had to be developed for use in multiple applications; regardless of whether there is a text editor or not. Components that you'd be silly not to develop through a text editor project.
You are trying too hard to justify that we not make a text editor. It feels like you don't want us to make a text editor at all. No one is on a path to burnout. Everyone is paid a full time salary to work on their respective areas. COSMIC development is doing really well.
GNOME users wouldn't be happy having to install KDE dependencies to use a KDE text editor which doesn't have a consistent look and feel on their desktop. Same applies for KDE users.