iPhone router saturation

Environment:

WNDR4000 - V1.0.2.4_9.1.86
iPhone 6S - ????

I need some brief validation please. My wife's iPhone is saturating my router. I have looked for similar issues,
but can find nothing like. She connects the phone at night for its charging cycle. Unfortunately, I know very little
about these phones, but apparently, in addition to charging, the phone undergos some kind of data synchronization
for cloud backup purposes.

When this process get rolling, it will absolutely smoke this router. To the extent that simply initiating a web access
can be a 2-5 minute erratic operation. Of course, we've come to mortal combat over this issue. But I request a
validation of changes I've made, to ensure a proper circumvention.

Briefly, I changed the router configuration to enable QoS, and changed the iPhone traffic priority to low. I am test-
ing it now as this is written, and it seems to have dropped the phone traffic considerably. In fact, as I'm watching
the router activity, I see only very intermittent activity.

The previous iPhone(a 4S, as I recall), seemed to do this synchronization during charge, but didn't clog the net-
work nearly like this 6S does. I've been enduring this issue for at least a year, and just to busy/lazy to dig into
the problem.

Does my circumvention sound accurate, and will I(she) encounter other unintended problems with the phone
operation during network use?


Thanks.