What you’re seeking makes a lot of sense. You should be able to create what works for you by installing one single wall oven

and then install a separate Speed oven or Combi Steam oven above it. (Either of those will offer you a smaller oven size than the 30 in. single oven below it) Some appliance brands do offer one unit that contains both of these with one control board but , FYI, many of us here are wary of those because if you get a mechanical failure, you can lose the use of both simultaneously.

I’ll have to research your suggestions -not familiar with speed or combi steam.. ty