Yeah, I am comfortable with most DE's, I'm flexible but I prefer KDE+Wayland.
Dolphin is poorly threaded though. For example: If I drag a large file from a network share to the desktop I can not drag another one to the desktop until the first copy have completed. If I connect my VPN or just an away-from-home wifi, Dolphin freezes, probably because it can't find the local SMB connections in the "Remotes" group.
I'm also watching COSMIC, it has a very well thought out architecture though I suspect the first version will be too simplistic in terms of features - for example vs Dolphin.
Yeah, the author normally rarely misses an opportunity to complain about KDE being too complex in his articles - and COSMIC aims to fall in that sweet spot between the extremes that are GNOME and KDE, while adding features like optional but native tiling.
The applet concept where applets live in their own process and communicate via Wayland protocols (behind a COSMIC API) is also less likely to break than GNOME plugins that are horribly injected into its bowels.
Given the toolkit, organized development and UX decisions being up-front designed with figma sketches, etc. that are reviewed before implemented, and having both paid developers and community contributors it has a lot of potential.