Hey! I can now finally input my answer and share a bit of code! I have been pretty active trying to rank up so that i could comment on this thread for so long. Anyways, so i have achieved this by doing what @Improper_Username suggested by using Tampermonkey, you can download the script i created by going to the dashboard on tampermonkey, clicking utilities and pasting the url in the box where it says “Install from URL”:
https://github.com/mawesome4ever/GameLauncherTamperMonkey/raw/master/Join.user.js
This script does exactly what Sema mentions. Looks at the URL gets the gameid from the page and the job id by adding ?gameid=1235 to the url. If the url is a games page on Roblox and has gameid in the url then it will launch the Roblox player. This is how i create the URL in-game (ALERT! Make sure to use game.JobId and not game.GameId as shown in the image as that doesn’t work anymore!):
Hope that helps!