I think this is an individual thing. People have different things they want and different scheduling. From what I've been reading in multiple threads the newfound "fiddle" or "fiddle faddle" term to mean refreshing to eternity (because the times are just next available vs old FP+ when you could select what time you wanted from a list of available ones) has been needed for people depending on when they went and what rides they were wanting and when. Some were doing in the parks, some while at the pool, some while at an ADR but it's not something that I would describe 5 mins every 1-2 hours because that doesn't jive with a lot of reports and even being realistic to some having their phone out even as much/little as you did would be "constantly tied to a phone".
To some people though their amount of phone usage doesn't increase or decrease appreciable enough to place
Genie+ as the culprit especially if someone has been during FP+ times. From someone who only did SB lines while at WDW a few weeks back we were on our phones because we were checking wait times and then I was also checking for mobile ordering or for Space 220 Lounge or for a different random ADR but I would say in the end it was probably less than when we used FP+ because I wasn't searching for that added component to our touring plans. On the other hand I can tell you my phone usage would have probably, personally speaking, increased with Genie+ due to the time in the morning needed to get it and start my list going AND trying to time out when I wanted my LLs to be. We typically park hop in the afternoon and I probably would used the same strategy I did back when we had FP+ by making selections for the afternoon in the second park, this may have needed me to check, hold off, check, hold off, etc on the available LL times so I don't book too early.
We had portable chargers with us period because
MDE itself is a battery hog (it'll run in the background unless you force stop it all the time and then when you need it it will be slower to pop up again if you do that). Even my husband who wasn't on his phone much (I am primarily the one who does the MDE stuff) needed to charge his phone. Smart phones are battery eater uppers a lot lol.