How do I check a user's current game info?

The title may seem unclear. READ ALL OF THE DESCRIPTION BEFORE ANSWERING.

No, I am not looking to build any form of exploit client (as what I am doing seems to be the case with what exploit clients also do)

I basically want to read game info from the client's computer. This is mainly to build a discord RPC client that can read a game's data and well, show to everybody on discord what you are doing basically. (with the case to hide specific details as the user wants)

The easiest way i've heard is to send an http request to roblox api's and get the users playing info but that requires them to have their settings on everyone (this isn't very optimal as maybe somebody big might use this but doesn't want anybody to join them)

Do you guys have any idea on how I could do this?

Please keep answers away from stuff like "use a dll injector", im NOT looking to make an exploit client.