I don’t think that rendering is the bottleneck at all. You can see my profiling results here:
Note especially what things I’ve tried disabling and gotten basically no performance change with them:
I’ve tried disabling AI, rendering microbe graphics other than the player, and disabling microbe sound. Those have no impact on the performance. It seems that around 30% of total time is taken up by physics and Godot scene tree updates, with 10% being our C# physics callbacks.