You totally nailed it. The actual syntax / API of constraint solvers are so simple they can be learned in no time at all. What actually takes time and expertise is modelling problems in this fashion and there are almost 0 real world (in size and complexity) examples out there for others to reference.
I have about 5 years of experience in MiniZinc solving scheduling problems but sadly all that code is locked behind closed doors never to be open sourced. I would love put together some fully worked constraint programming examples complete with containerisation / visualisation/ modeling etc but the barrier to doing so is finding problems that are actually worth solving and have open source data to work on.