I tested your project on a Pixel 3 and got the following results:
C2: first switch ~232ms, later switches ~100ms
C3: first switch ~170ms, later switches ~100ms
So according to this, the C3 runtime is faster in this case. I don't know why other devices would be different, maybe specific hardware is better or worse in different cases.
Besides, C3 has a new feature that helps you hide this from the user - there's a built in memory management action "Load layout images", so you can load the next layout's images in the background while the current layout continues to run, and then switching layout will be instant. This feature is not available in C2. If I use "Load Layout 2 images in to memory" on start of layout in Layout 1, then it can switch layouts in around 5ms, which is far faster than you can ever achieve in C2.
So as far as I can tell C3 is both faster at loading layouts and it has a feature to help guarantee that layout switching will be instant, which works here.