Ran Lutris and workarounds (according to @mtodor's instructions) under

Ubuntu 16.04 LTS

as well

(since I have a dual-boot: Ubuntu LTS for work, Antergos for gaming, usually).

- Updated entire system and made sure to have the latest Mesa, so glxinfo | grep "OpenGL" puts out:

OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD TONGA (DRM 3.1.0 / 4.4.0-22-generic, LLVM 4.0.0)
OpenGL core profile version string: 4.5 (Core Profile) Mesa 17.1.2
OpenGL core profile shading language version string: 4.50
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 17.1.2
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.1 Mesa 17.1.2
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.10
OpenGL ES profile extensions:

=> same error, same problem!