Even though digital joystick controls are available for non-Steam games, and sometimes it is better depending on the game. If you're looking to use the 256-level analog mode for more precision, there is a way.
Simply add the launchers for other platforms into Steam - Epic, Battle.net, Origin/EA
platforms have been tested to work.
1. Add the platform to Steam. https://help.steampowered.com/en/faqs/view/4B8B-9697-2338-40EC*** Add the launcher, not individual game ***
2. From Steam, launch one of the other platforms (Battle.net for example).
3. Launch the associated games from the launcher (Overwatch for example).*** Must remember to disable auto-start for the launchers (so they don't launch automatically upon reboot) ***