Seeing that the devs seem to be ok with a steam release, what if we opened an issue to keep things up to date with what we need to do, that way when someone else asks questions we can just refer them to the issue where they can see what things are blocking a steam release.
And the things blocking for steam release could be very obscure "figure out mod issues" or add tutorial campaign and stuff like that.
I have axe thrower in Endovetico, and I used a javalineer animation there, but with a hissing sound instead. It worked well until we have a proper animation.
It depends on a platform so generally we just provide options to control quality.
About the first screenshots you could do the following:
Disable Post-processing
Disable Shadows
Disable Unit silhouettes
Disable Particles
Set Model quality to Low
Move the Shader rffects slider to the left
Disable Water effects
Set Texture quality to Low
Set Texture anisotropic filter to 1x
Also you could try to test different combinations of OpenGL/Vulkan (Renderer backend) + GPU skinning on/off