I took my own passport photo with my mirrorless camera, and a whiteboard as the background. It took a while to get it right, with no bright spots on the background and now shadows. It was accepted.
A tip for 10 years from now: take the picture with diffuse backlighting and you can easily blow out the background completely. For example, a sheer curtain in front of an outdoor window is just about perfect.
Ten years from now, hopefully you won’t have to be taking and printing your own passport photos. I haven’t done that in at least a decade, maybe two, in Europe. I go to the office that handles it and there’s a machine there that takes your photo.