New Battle.net update Version 14542 breaks Linux compatibility with Wine/Proton via Lutris or Steam and will only display a gray screen.

Workaround is to delete the update folder Battle.2.net.14542 under $wine_root$/drive_c/Program Files (x86)/Battle.net/ and then start the client again.

Update workaround: Set WINE_SIMULATE_WRITECOPY=1 environment variable in Lutris