I just tried lutris for the first time today to install a steam game and imagine my disapointment when I got an error message when steam was trying to install the game. The same as from this thread, e.g. steam content servers unreachable.
Fixing it was really easy however. A solution is listed here
I’d post a quote but apparently I can’t because it has too many links. Hopefully this can be added to the steam runner installation, or at the very least be given as some sort of option.