I updated my pc and I don’t remember what was. Pacman change one package by other and all the icons and applications show extremerly big. I was searching and I have installed wayland and xorg, so I don’t know if it comes from xorg or wayland. I tried to use other DE or WM (qtile) I have the same problem. I have te rescale all and some applications like virtualbox still showing big.
Edit: After a little search I found what package was updated in my system: xdg-desktop-portal-gtk was updated 2021-11-10 the same day that I updated my pc.
I hope it can help.