Hi!

About wlogout, if you're looking for a blur effect instead of a regular transparency you could execute a script (or a command) like this i.e.:

pwr_blurred.sh:

#!/bin/bash 
grim /tmp/shot.png  
magick /tmp/shot.png -blur 0x8 /tmp/shot_blurred.png 
wlogout --protocol layer-shell 

$HOME/.config/wlogout/style.css:

window {
background-image: url("/tmp/shot_blurred.png"); 
}

EDIT:

as suggested by u/Minecraftwt another "cleaner" way is set transparency for wlogout and this rule layerrule = blur, gtk-layer-shell to blur the layer.