GloriousEggroll has released a new custom build of their Proton fork. The new version comes with fixes for Borderlands 3 and Remnant: From the Ashes.

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

New in 5.5:

So I'd like to preface that this is a pre-release that has a massive amount of media foundation/mfplat wine patches. A huge thank you goes to Derek Lesho (Guy1524) for getting this stuff working and taking the time to help me get it working with the correct dependencies in proton.

What this does is allows mp4 playback in MANY titles, including UE4 -and- Unity engine games. This fixes a lot (not all, but a lot) of issues surrounding media foundation/mfplat without the need for the 'mf-install' workaround that has legal issues and limitations, and is much safer for us to ship.

Tested fixes:
-Fixed borderlands 3 lilith in-head videos and 'watch the monitor' video bug
-Fixes Remnant: From the Ashes intro videos, intro menu, character menu
-Fixes intro video on Bloodstained: Ritual of the Night
-Fixes mp4 playback issues related to Crazy Machines 3

Still broken:
-Borderlands 3 intro narrative with Marcus's voice on new game does not play
-Spyro is still broken
-Probably some other mp4 related titles

Additional updates:
-A small patch has been added that should fix sunset overdrive from crashing on launch
-Two warframe launcher regressions have been fixed
-Mouse input fix patches which were added to wine-staging for Mount & Blade II: Bannerlord
-Lots of gstreamer plugin related work has been done/added in order to get media foundation stuff working. This was also cleared with aeikum and kisak from Valve personally, and deemed -ok- to include in my repository. This means it is safe to continue to link in Valve's issue trackers, unlike the 'mf-install' workaround. HURRAY!

Additional notes:
-Not -all- mp4s are fixed. There are still some that have problematic formats that are being worked on.
-Also coming down the pipe soon will be WMV playback fixes. This is to be handled after the mp4 issues are sorted.

Download Proton 5.5-GE-1 from GitHub
Installation Instructions