hello Mr sidehack, welcome to blf! It is always good to see new project from forum members! Have you seen these different drivers?
mtnelectronics has some buck drivers similar to you: Buck
loneoceans making a buck boost driver here: Lume1-FW3X: Constant Current Buck-Boost & FET Driver with Anduril1/2 + RGB Aux
lexel make a lot of different kind of driver here: Lexels driver compilation
Many driver use open source firmware which is actually easy to change to just single or multi mode with a code definition I think.