Hello dluco'/run/media/<user>/' is the default mount path of udisks2, used by gvfs of thunar.If you want to change that you can try other tools for (auto)mounting: see https://wiki.archlinux.org/index.php/Udisks#Udisksudev rules are not that easy to use, but I think you will find a tool already doing what you are looking for.Cheers.
Ok, I think I have a fix. Deleting my Thunar config files helped. But here's the tricky part:You know the "~/.config/Thunar" directory? That apparently is not the Thunar config file location. Instead, I removed "~/.config/xfce4/xfconf/xfce-perchannel-xml/thunar*". After restarting Thunar, my Trash can worked correctly.