material-decoration VS plasma-applet-tiledmenu

Question, have you considered implementing locally integrated menus like in this decoration https://github.com/Zren/material-decoration ?

There is this project but I am not sure its the best way. It has an Arch and an rpm package, so you dont have to build it yourself.

You don't need empty space for that. GTK lets you drag from anywhere on the headerbar, buttons included. Similarly, the KDE material decorations which implements LIM also lets you drag from the integrated menubar. Buttons don't need to reduce the draggable area at all. Not that I want Plasma to have CSD of course, but having LIM available in official decorations would be nice.

You can get rid of menu bars. Most KDE apps use a hamburger menu by default now instead of a menu bar. Pressing CTRL+M lets you switch between hamburger menu and menu bar in KDE apps. KDE has no CSD tho and that's not something that's going to change, but you can move that hamburger menu to the title bar in window decoration settings. If you use the Material Decorations theme, you can even have your menu bar inside of the title bar. Or you can just use GNOME apps in KDE. That works too. But I mean, you've already said GNOME suits your workflow perfectly, so just keep using that. It doesn't seem like you've got any reason to switch to KDE.

Link to the project's github.

My favorite implementation is locally integrated menus; this Material Decoration theme has it nicely implemented, but unfortunately it doesn't work on Wayland. I hope it'll manage to land in Breeze at some point.

There is a KWin decoration that supports this: https://github.com/Zren/material-decoration

Zren's Material decoration has an option to hide it, Breeze windows decoration doesn't.

might be easier to just remove the title from zren's material decoration then

I think there are already Plasma menus that do almost the thing you want. For example https://store.kde.org/p/1160672, https://store.kde.org/p/1367167 or https://store.kde.org/p/1367178 . Maybe it would just be better contributing to those instead of starting completely from scratch. But in the end you decide.

"tiled menu" from the KDE plasmoid shop or from here

If you want something just like the Windows 10 start menu, you may want to consider the Tiled Menu widget.

I would use the Tiled Menu plasmoid, as busy_biting suggested. It's highly configurable, though a bit clunky in some edge cases. Very functional and good looking, however! I'm not going for a Windows 10 look at all and yet it's what I stick with because of how great tiles can be.

Tiled Menu, the launcher that did tiles better than what Windows 10 did.

https://store.kde.org/p/1160672/ Tiled menu is good one

On Plasma you can download the tiled menu which has on option that makes it full-screen