Fix the blur with picom
uninstall picom
The blur is avalaible only for the git version,
So if you have it from pacman you have to remove it.
sudo pacman -R picom
Install picom
This is the git:
https://aur.archlinux.org/packages/picom-git/
git clone https://aur.archlinux.org/picom-git.git
cd picon-git
makepkg -si
Start it with i3
I have to add experimental-backends in my config..config/i3/config
exec --no-startup-id picom -b --experimental-backends
Picom conf
I have nothing to add on it but you can modify things like you want..config/picom/picom.conf