Total newbie question before I buy: will Garmin's RV 770 LMT-S work?

Hi. Was chatting with Garmin and they say they can only “guarantee” their proprietary maps. Ok fine. But, their owner’s manual for this product doesn’t say whether I can get open source files into it.

Will this unit work with open source files like OSM?

My purpose is to take a year long road trip from the US to South America.

I have an older Garmin 550t that I used for hiking. I recall that I could get hike route files from just about anywhere and put them into the 550t; however, the base maps I did buy from Garmin.

So, if I use OSM with this new Garmin 770, does this impact my ability to work with downloaded routes and have full functionality of the unit?

Thanks for any advice. It about $600 with the back up camera, so I want to do this only once: :smiley: