Hi Phil--
Don't know how much help I'll be on current installations. My 2552 was built in late 2018 and early 2019, and delivered in February 2019. There may have been some changes in the past year-plus.
The earliest factory solar installations on Phoenix Cruisers were done with Samlex solar kits, and all components were provided by Samlex in the kit. Samlex was a major solar supplier, and provided what was considered a reliable (if not cutting edge) kit. Phoenix was reluctant (refused) to incorporate different brand components--such as the controller--at the request of the buyer, likely because they were new to solar installations at that time and didn't want to take a chance on providing an inferior installation.
That policy had relaxed some by the time they did my installation in late '18/early '19. An item on their option list then was the Trimetric TM-2030 battery monitor (which was available with or without solar). Trimetric made a solar controller (the SC-2030 Solar Charge Controller) which was designed to interface seamlessly with the battery monitor, and that was the controller that Phoenix installed when the battery monitor option was specified. I don't know whether they used that same solar controller if the buyer did not request the battery monitor, or if they used the Samlex controller they used before.
In any case, the solar option when I ordered was about $3K, and in my case it included (2) 150-watt Samlex panels, the Trimetric SC-2030 controller, and associated wiring. I also had the Trimetric TM-2030 battery monitor, of course, so that completed my system. I must say that the system has worked flawlessly, and I have been very happy with the result. Since I specified the AGM batteries, the system requires virtually no routine attention or maintenance, and as long as the coach is parked where there is a little sun, my house batteries stay at 100% charge when not in use with no effort from me. My system as installed does not have a mobile app to allow system review remotely. I have not researched this option, since my PC is parked at my home and I haven't had that need. I don't know whether it is possible with this particular setup.
Again, things move rapidly in the RV building business, but this is what Phoenix was doing a little over a year ago.
All the best, Mike