Didn't know RM had an app but certainly not surprised it's poorly rated. I don't know anyone that LIKES RM most of us just tolerate them because they came with the boat. Since you have Seatalk ng an inexpensive Nema 2000 to Seatalk ng adapter cable would allow use of any new MFD. I don't spend any time at the nav station while the boat is moving since the 90's when my GPS was there with my paper charts.

 

As I basically am sailing in waters I have sailed for 40 years I only refer to my plotter to show my track and heading and see how current has affected my journey. There are "intense" area such as Plum Gut or the race and one needs to not let your guard down as the current can run 4 knots or so.
PAY attention to what around... pay attention other boats... pay attention to your charts... pay attention to the tide/current tables.
PAY ATTENTION

 

While not as salty as some, my use of a chart plotter is mostly for the shoal areas here in Florida. Once underway, if The Better 9/10ths is on watch, I can at least check heading, wind and depth from down below. Aside from that, I'm learning my charts and celestial navigation because, there will come a time...!

 

Well, no complaints thus far, but, then, it's early.

 

I have had RM electronics since 2016. The app allows you to mirror the MFD on your iOS/Android device. Nothing else. I gave up using it after one of RM's update, broke the ability for my eS78 to display depth.

I get more functionality from a navigation app (Aqua Maps) on my cellphone.