So, we have had a taste of Platinum, learned some dear lessons about our weaknesses, and have been sent back down to gold. Do not get too discouraged. It is fine to go down to a lower league where the foes are not as formidable.
First tip, do not waste ability points on the front mortar. You can just punch through the wall and take it down. Save your abilities for the launcher and other threats.
Another level 11 base for you to much on. This one is a much more standard design.
A level 12 base for our fourth base. There is not much available to orbital strike, snipe out targets as necessary.
Another level 12 base. I would suggest to come in from the left since the defenses are not as compact on that side. You can orbital strike this base at the mortars and the beams.
And finishing off with one final level 12 base. This is an… interesting design. At the very least, it is not very typical of a level 12 base. There are multiple feeding spots if you start off to the left, so feel free to feed while you take out mortars (which you can orbital strike).