WebCord is an “alternative client” for Discord, although it’s just running the Discord webpage in electron. Recently it updated its electron version so it supports sharing audio as well as video.
I tried it out today on mint (x11, pulseaudio) and it works flawlessly.
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Sorry, misread that part. I was referring to plugins, which can increase CPU usage, and backend, which you can choose between vencord and webcord.