8 000 x 8 000 is about 2,4 times more pixels than 18 000 x 1500. More pixels needs more RAM to render. 32 GB is most likely not enough to render 8K resolution output. If your system is running out of RAM, then it either will crash, or start using swap file on your disk, which is thousands time slower than RAM, therefore huge estimated time actually makes sense. You have several options how to solve this issue, a. add more RAM (64 GB is considering minimum for rendering with Corona these days), b. reduce output resolution until scene will fit to available RAM, c. try to optimize the scene (remove all unnecessary render elements, bake and delete lightmix, reduce textures resolution, close all unnecessary programs while rendering).