Overall I like what you're doing here - power distribution in a typical home is less modular and extensive than I would like and this is a good step in that direction.
I don't think the extension cords are a problem because they're not in the wall (and I see actual Romex used in the wall).
However, I would take the time to carefully research exactly what pieces of this are, and are not, code compliant. Not because you need to redo it, necessarily, but because it is a very impactful way to learn these things and learn deeper concepts of safety and failure behind the rules. Nothing stays as well learned, or remembered, as details relating to work you have actually done.
A lot of lessons learned, hard lessons learned (like fire, expensive equipment damage, injuries and blindness, and big sparks) have happened to get electrical code to where it is.
I don't think the extension cords are a problem because they're not in the wall (and I see actual Romex used in the wall).
However, I would take the time to carefully research exactly what pieces of this are, and are not, code compliant. Not because you need to redo it, necessarily, but because it is a very impactful way to learn these things and learn deeper concepts of safety and failure behind the rules. Nothing stays as well learned, or remembered, as details relating to work you have actually done.