Hello, Audio Engineer with some little knowledge regarding AI here.
What you think of is restoring frequencies, this is possible, and commonly used in plugins for audio restaurization. I might be mistaken, but this does not improve the bitrate, but the perceived quality (which is still lossy).
I don’t think that there is a real interest to upscale quality (not perceived quality), especially for longer (> 1 minute) material.
Thank you for sharing this article! This prevented me from working on projects and software. Not only FOSS projects should refrain from using Discord. Community-driven projects like Skywind are barring themselves from helping hands, they desperately need, by using proprietary, privacy-threatening software as their way of communication.