The problem with replacing Discord isn't the tech or features. Discord doesn't do anything special that hasn't existed in other software for 15-20 years.
The key difficulty is overcoming the network effect. All the big streamers use Discord, which means their millions of viewers are going to use Discord also, which means that most of their friends will too, and thus, you have a default app that almost everybody uses.
It took a massive amount of effort for me to just get three of my friends to sign up with Matrix and join a group server for gaming, and two of them stopped using it after just a month or two. I only have a single friend who is still using it, and they only use it when the two of us are gaming.

Lt. Eva Lee from Red Alert 2. Yeah Tanya was hot too, but something about how Eva talked just made me swoon lol.
I will be so happy when the era of client-side anticheat is over. I think it will happen eventually, especially now that Valve is releasing the new Steam Machine and has been so successful with Proton-based gaming lately.
Plus, Windows getting so much worse and the zero days and exploits of these kernel-level anticheats will put pressure on the devs to move away from them imo.