Civilization VI [Steam] is a really fun game and it's damn good to have it on Linux, but performance has been an issue. Aspyr Media are aware of it and they are looking to improve it.
From their forum posts (source):
QuoteMultithreading is supported now, but not on the rendering path. Our implementation of OGL has issues with multithreading unfortunately, and we are actively looking at alternatives.
Also, in response to this question "Do you mean alternatives for OpenGL (everybody knows what that could be..) or alternative implementations of OpenGL ?" (source):
QuoteBoth! All options are on the table for optimization.
It's good to know it's going to see good post-release support from Aspyr, but I never doubted it would for a moment.
Hopefully, we will continue our playthrough on Twitch again this Sunday.