camera settings – Product photography sharpness?

I’m doing a few pieces of product photography but has to be amazon approved so on a 255 background I took this shot but sadly every time you zoom a little into the photo it’s not as sharp as I’d like. I only used a lens which only goes up to f5.4, is this the issue? Or is it that I need to fill my whole frame when taking the shot to ensure large enough pixels to work with when cropping or resizing? I only have two soft box lights to work with so when I took this photo I was on iso 400 which I have read that this would be best used on 100 to reduce noise. I also took the shot on 125 shutter speed as Didn’t have a shutter release until recently ordered one. Any tips on how to improve would be greatly appreciated. With amazon having the zoom function really need these to be as sharp and clear as possible enter image description here