Just add the games through Heroic to Steam. You have to restart Steam for that to take effect. You can also configure Heroic to automatically add every newly installed game to Steam.

In Steam you can then adjust the controls. Just don’t have Heroic running when you start a game or Steam won’t know whether a game is running or not.

As the games are still running through Heroic all the achievements will work the same as before. Although I didn’t even know that Heroic supported achievements.