Maybe too simplistic for what you’re looking for, but Buzz Aldrin’s Space Program Manager allows you to do some of it.

It’s based on an older title IIRC, and it’s a game more tuned towards education with relatively few graphical elements. You won’t be flying missions directly, nor do you have sandbox capabilities, but for mission planning / R and D / mission control, there is some fun to be had.

I go back to it occasionally.