I replaced the factory in-dash unit in my 2010 Chevy 3500 based RV with a Kenwood/Garmin unit that had GPS, HD and SirrusXM (no Apple CarPlay or Android Audio at that time). It was simple to find a unit and all the cables necessary.
Also replaced the in-dash unit in my 2016 Sprinter based RV with a very similar unit. A bit more difficult to find the cables since the Germans use different connectors, but I finally found everything I needed.
A bit more difficult to do in newer vehicles like my 2020 Jeep since many manufacturers have less space available behind the dash so one needed to find a half-depth unit. That wasn't an issue when I did the replacement in my 2011 Jeep though.