Mod editor creation?

I am currently working on a game where we would love players to have the ability to create their own maps and mods using blueprints. We’ve seen this done using UT4, Squad and Ark which all have mod editors downloadable from the epic launcher. These are cut down versions of the UE4 editor with features such as packaging game etc removed.

How would we go about creating one for our project, not including game source code, if possible limiting modders ability to edit existing blueprints etc and only create their own and having the cut-down editor with only relevant modding functionality.

Also, assuming this is something we CAN do, is this limited to distribution through Epic’s launcher?