I've found a way to make i3 work with KDE plasma, xfce, and lxde.
The configuration with KDE is the less bugy in my case and the only one where the cation keys (volium and brightness control) works properly.
For KDE: There is a guide in this link https://userbase.kde.org/Tutorials/Using_Other_Window_Managers_with_Plasma
And here is an other one: https://medium.com/@vishnu_mad/using-i3-window-manager-with-kde-plasma-c2ac70594d8
Personally i've used the methon on the second link and i've added some of the commands that I've took on the firs link, to my i3 config file.
In the end i've added the fallowing to my config file:
#____ Plasma Integration BEGIN _____
#Try to kill the wallpaper set by Plasma (it takes up the entire workspace
#and hides everythiing)
exec --no-startup-id wmctrl -c Plasma
for_window [title="Desktop — Plasma"] kill; floating enable; border none
#Avoid tiling popups, dropdown windows from plasma
for_window [class="plasmashell"] floating enable
for_window [class="Plasma"] floating enable
for_window [class="krunner"] floating enable
for_window [class="Kmix"] floating enable
#for_window [class="Klipper"] floating enable
#for_window [class="Plasmoidviewer"] floating enable
#____ Window Rules ____
#____ Avoid tiling for non-Plasma stuff ____
for_window [window_role="pop-up"] floating enable
for_window [window_role="bubble"] floating enable
for_window [window_role="task_dialog"] floating enable
for_window [window_role="Preferences"] floating enable
for_window [window_role="About"] floating enable
for_window [window_type="dialog"] floating enable
for_window [window_type="menu"] floating enable
#____ lol idk what programs this thig take care of ____
for_window [class="plasmashell"] floating enable;
for_window [class="Plasma"] floating enable; border none
for_window [title="plasma-desktop"] floating enable; border none
for_window [title="win7"] floating enable; border none
for_window [class="krunner"] floating enable; border none
for_window [class="Kmix"] floating enable; border none
for_window [class="Klipper"] floating enable; border none
for_window [class="Plasmoidviewer"] floating enable; border none
for_window [class="(?i)*nextcloud*"] floating disable
for_window [class="plasmashell" window_type="notification"] floating enable, border none, move right 700px, move down 450px
no_focus [class="plasmashell" window_type="notification"]
#____ Plasma Integration END _____
I found this article that shows how to combine xfce with i3 :
http://feeblenerd.blogspot.com/2015/11/pretty-i3-with-xfce.html
But in my case the brightness key doesn't work even with xfce lol (i mean, even the normal xfce, not the one opened with i3)
Also I've found this video that shows how to transform KDE default window manager in to a "quasi" tiling window manager :
https://www.youtube.com/watch?v=n4pppzPxD3Q
I've also found that you can combine i3 with LXDE by replacing the line window_manager=openbox-lxde
by window_manager=openbox-lxde
in ~/.config/lxsession/LXDE/desktop.conf
and you also need to remove the line @pcmanfm --desktop --profile LXDE
in ~/.config/lxsession/LXDE/autostart
but again there's a problem with the birghtness and sound controle