How do I remove checkered background

The solution might be one quick step. If you want the results to be opaque after cropping a Background layer, select Delete Cropped Pixels before cropping, in the options bar for the Crop tool. Compare how it works on the left and right sides of the demo below. The only difference is that on the left, Delete Cropped Pixels is enabled.

I know that is not obvious from how the option is named, but I realized it might help after remembering that when Delete Cropped Pixels is disabled, the result is not clipped by the canvas, and that requires transparency. I thought maybe enabling the option would prevent transparency, and it turns out that is correct. So, I actually learned something by trying a solution for your question: Until now, I didn’t realize Delete Cropped Pixels could do this too.

If it turns out that this was a very simple solution all along, you may want to reconsider writing such an angry post with all the capital letters denigrating the transparency checkerboard as “useless.” It’s a valuable indicator that professionals use to clearly recognize the difference between an actual transparent background, and an opaque white background. You may find you get better help if you ask politely if there a simple solution, instead of publicly demonstrating to other professionals that you do not want to respect a valuable feature they need to use in commercial image production (for example, when a client requires all images to have transparent, not white, backgrounds, so you need to be able to verify that as you work).