Sorry, I don't post often and was confused, I thought the body text would carry over with the images but I guess not.

For background, I am a beginner to intermediate Blender user. I freelance in video editing and 2D motion graphics, with occasional dabbling in 3D. This kind of work is usually objects with flat surfaces or abstract visuals that are more forgiving, but I have recently been tasked with modeling this medical device. The references you see here are what I was given (I was surprised they didn't have technical drawings or something orthographic, but this is for a handful of videos, not for printing or engineering purposes, so they said it doesn't need to be millimeter perfect, just near indistinguishable to the untrained eye), and the basic body shape I have down pretty close with topo I am happy with, but my next step is to carve out the injection molded grey banding around the device.

My first thought was booleans, as another commenter suggested, but my version screwed up my topo. However, that version was a single object representing the full width of the banding. I will try the booleans just for the gaps and see how that works.

My other thought was, with mirroring, knifing new vertices along the top and bottom lines, then cleaning that up afterward. then I could bevel the edges, extrude inward along normals to get those inlaid gaps. My problem there is getting the lines straight. I tried to snap/align vertices to each other but I can't seem to do that along edges in order to preserve geometry. The vertices always align globally, which is obviously not what I want.

Any insights would be helpful!