Discord for mobile devices includes some useful features such as the ability to video-chat while playing smartphone games. However, some of them are only available on Samsung Galaxy phones, due to the version of the app in question only being found on this OEM's in-house Galaxy Store. Luckily, it seems one of them is now no longer exclusive to this series.
It is Mobile Voice Overlay, which, as the name suggests, maintains access to the app's voice-chat controls from an interface that persists over all apps. XDA correspondents have reported its detection in its latest betas (versions 19.1-.4) for its app from the Google Play Store.
This setting has been found to work on units of the Google Pixel 4, OPPO Find X2 Pro and OnePlus 5T. It requires a permission to draw over other apps in order to function. Hopefully, it will also find its way into the stable version of this app soon.
Source(s)
Google Play Store via XDA