Hello,
I m opening this awesome grid with program windows.
I can sort and move with arrows via all windows.

But is there a way to close active window from grid with shortkeys? like alt+ f4?
I tried above and few more but I can't

KDE Plasma Version: 5.18.5
KDE Frameworks version: 5.68.0

Cheers!

when you are in Grid mode no, as the window is not technically active at that moment, only selected. You can close a window with the shortcut once it is indeed active, e.g. selected and the Present Window mode is closed.

Nocando. You can only move around in grid mode. In present windows you can assign right-click to close. For more functionality you'd need parachute. At some point I assigned custom corner bindings with xdg-hotcorners to get skippy-xd and xdotool commands ( to emulate key shortcuts), go figure. But, overall, for a more combined grid/present windows functionality, you'd need parachute. Then again, it doesn't offer much in terms of keybinds if you prefer that.