Steam is one of the most popular platforms for desktop games but you'll need to do a bit of setup to make sure your game can make the most of Steam specific fun...
I currently have quite a big to-do list, but when I get time I'll look into updating it.
In the meantime, the manual outlines what the Steam options are in the NW.js dialog: construct.net/en/make-games/manuals/construct-3/interface/dialogs/nw-js-options
So as a starting point, I'd assume you don't need to manually add the in-process-gpu arg if you check Export for Steam.
The Enable Devtools checkbox should handle whether the game allows F12 to open devtools, so you don't need to add the devtools arg if you're leaving that unchecked I think.
Thanks for getting back to me. No rush for this if you have a big to do list :)