The settings listed under “Web” are for the Plex Web app, which is the Plex player app/client you use when you access Plex from a browser. And the settings listed under “Server” are the only settings for Plex Media Server.
Since the settings for Direct Play are under Settings > Web > Player, that will only affect direct play when using the Plex Web app from that browser, because it is listed under “Web”.
