The comic in question was Action Comics #346. The advertisement under discussion can be found here. Given the scale of those toys and the multiple battlefields the kids seem to have built, that’s some massive diorama.

In case you hadn’t spotted it (I hadn’t), there is a like button available just above this bit for you to share your favourite Planet Karen comics at the Book of Face, and in fact all sorts of other places. It’s the one in the middle with the squiggly icon with “like” underneath it in tiny, tiny lettering, but I’m working on making it easier to spot.