I'm following this tutorial by Unreal Engine itself, but I don't have a Steam overlay popup like I'm supposed to, (according to the tutorial.) And actually a lot of people have a similar issues like this.
What I have done / tried is:
Enabling Steam overlay (in Steam settings, but it was already enabled)
I've already edited the DefaultEngine config file
I'm playing my game (in Unreal Engine) from the Standalone Game option
Searching this up, re-watching tutorial, looking at tutorial's comments
Enabled the Online Subsystem Steam plugin
And I still don't know what the issue is. I've also looked at this thread by the Unreal Engine community, but it didn't help that much.