The reply from Honda and the warnings on the machine are from the lawyers to cover Honda. Some states (I am in Utah) allow you to register your off road vehicles (including ATV's, Side x Sides, and dirt bikes) as on road legal with some modifications to the machine. Mostly its safety devices like blinkers, horn, mirrors, etc. and you must carry on-road insurance.
Honda makes world wide products and for many years in other countries there have been from factory street legal versions of some of their models that are only "off road" in the USA. I would expect if the Pioneer is street legal from factory in another country it would NOT have the same tires and likely a street legal radial tire.
Since you are in the USA expect Honda to always say its not intended for street or pavement use. If they say otherwise and someone is involved in an auto accident it opens Honda up for law suits.
I ALWAYS make sure I am in turf mode when on pavement and can feel it in my machine as if NOT in turf mode the rear will push the fronts into turns. I have a 2017 1000-5 Deluxe that might not have the same system as yours however I find that the engagement to turf mode to locked rear diff in 2wd mode to be cable actuated and those cables stretch and require adjustment. There is a section in the owners manual for my year that shows how this process is completed. Mine is lever activated from turf to 2wd, to 4wd, to 4wd with front diff lock and if the lever is in the correct position it can't slip into the other modes.
I agree with others this shouldn't be an issue under normal times pre-covid to require that much time at the dealer. I hope you find resolve to your issues!