"Technical details: The pactl tool is required to display this page, but could not be found. You may be able to install it using your package manager; either way, please report this packaging issue to Solus"

I don't have a Github account so I'm reporting here.

The big problem with this situation is that the keys we use to sign our system aren't upstream keys (like Canonical's), so it would be worthwhile to talk to Epic Games to propose a solution that doesn't involve spending thousands of dollars on keys.