Tried out Win-Kex v2 (I hope this is the right forum for thoose questions too)
And tried out Seamless mode in win10 (WSL2).

When using maximized windows, they dont respect the border of the top kali bar/panel, so the windows becomes too big and hide behind the top bar/panel.
When maximizing the Chromium Web Browser, it gets maximized but when trying to undo this, it does not work, and the window cannot be moved, the only way to move it is to check the "Use system title bars and borders" options so you can move and resize the window but it looks really ugly and there are no buttons to operate the window.

One way to reach windows that have been maximized beyond the top panel is to unlock the panel, so you can move it down and access the maximized windows.

Also, I notized that it does not respect the z-index of windows, so windows windows can be hidden behind kali windows even if they are in focus.