Not suggesting any big things here... All I propose is to have the options for toggling the canvas overlays (empty canvas, heat, template) directly within the canvas editing screen instead of putting it in the sidebar, kinda like Google Maps. I think the sidebar version would be preferred in mobiles, so you could make this desktop only.

Alternatively, you could allow the user to place pixels on the canvas even while the sidebar is opened, like the way it was for the first 48 hours of the event. Also ensure the right side of the color palette is not hidden by the sidebar.