GloriousEggroll has released a new custom pre-release build of their Proton fork based on the latest  Proton release.

This is my build of Proton with the most recent release of vanilla wine, has ffmpeg enabled for faudio by default, and all of Proton's patches ported over to be applied to wine, as well as wine-staging and vkd3d.

All patches:

-Warframe screenshot F6 patch -FFXIV Launcher patch -Mech Warrior online patch
-Assetto Corsa HUD patch -Vulkan child window patch
-sword art online gnutls patch
-d9vk integration
-vkd3d integration
-protonfixes integration
-FAudio with FFMpeg enabled (fixes audio/voices in multiple games)
-All of Valve's wine proton patches. Yes. All of them.
-wine staging patches
-various wine hot fixes for wine functionality that fix regressions per version

Change log:

-controller fix for warframe - allows controller profiles to be loaded only if a controller is plugged in. fixes crash if no controller plugged in after 5 min.
-vkd3d updated, allows WoW to be played using proton via lutris (disable dxvk in lutris)
-more metro exodus vkd3d fixes
-wolcen lords of mayhem 'blob head' fix
-detroit: become human patch added
-need for speed world launcher patch added
-wine+ wine-staging updated to 5.4
-dxvk updated to latest git
-faudio updated to latest git

Known issues:

-MHW broken since last patch.
-MK11 broken since wine 5.0
-Injustice 2 broken since wine 5.0 (did not work here, but have had it reported working in 4.21)
-Borderlands 3 does not work with vkd3d yet

Download Proton 5.4-GE-1 from GitHub