I know the cage you’re talking about... seen it at a pet store and it looked WAY too small for a green cheek, or any bird really. GCCs are very active birds that need a lot of space! Cage width is much more important than the height, so getting a tall and narrow cage is pretty pointless.
I made this mistake when I got Kermit; he was in a 24x22x58 pagoda style cage (keep in mind your cage is only 18x18) and he stayed mostly in the top half, only coming down to the bottom to eat and drink. Once I upgraded him to his 32x23 dometop cage, he started using all the space and seemed much happier overall. Kermit used to avoid going back into the cage when he was in the smaller one, but now he happily hops right in when I put him near the perch. He even screams a lot less! It’s amazing to see the difference a bigger cage can make.
I would recommend a 32x21 flight cage, or if you have the money, a 32x23 dometop or playtop cage. The dometop/playtop cages tend to be a bit sturdier and come with additional features, such as metal trays, seed guards, and feeder doors. Flight cages are a bit more basic, but still great and less expensive. I have an A&E flight cage for my cockatiel, Ducky.
Here are pics of my birds cages to give you an idea of the size and setup:
Here are some links to appropriate cages:
http://a.co/d/7YUKEd0
http://a.co/d/32PmfkJ
https://www.birdscomfort.com/drop_door_parrot_bird_cage.html
https://www.birdscomfort.com/double_playtop_bird_cage.html
https://www.birdscomfort.com/large-elegant-style-flight-bird-cage.html