Hi !

I am a programmer but have little experience with UI and graphic programming, much less with graphic design

I'd like to work with someone else or a team of few people on making new Styles and themes for KDE.

minimalist and simple has been the key recently and they are the most popular. no doubt about it.

but with 1080p 27" inch screen getting cheaper and cheaper.
desktop real estate is not something we must optimize so much anymore.

I'd like to work on a new Task Manager that is very eye candy but not necessary space efficient. I got many ideas actually.
window decoration could also get more funky

anyone with me ?

Just as some details, it seems you want to develop a Plasma theme here. You can find documentation to do that on KDE Techbase (techbase.kde.org).