Well done on getting the refund.
The mobile pass might seem daunting initially, but I had my first mobile Interrail pass last September, and it quickly became quite straightforward to access it in the app, load new journeys, and so on. I assume the Eurail version will work just the same way. Probably the only major "gotcha" is that the associated journey planner is not very reliable: it doesn't seem to be updated frequently with timetable changes, and some services are just not included at all. So the usual advice is to do journey planning in some other system (as you're already used to doing, presumably) and just use the app's journey planner for those journeys you actually want for the pass. As I recall, the user guide on the Interrail/Eurail website is helpful, and there's also a step-by-step guide on the "Main in Seat 61" site:
https://www.seat61.com/how-to-use-a-eurail-pass.htm#how-to-use-a-mobile-pass