Let's face it, no one else but you know what bike handling skills you have and how comfortable and competent you are as a rider on varying surfaces.
I'm not a mtbiker either, but there is single trail and there's single trail, but what I can say from experience is that those tires look very very capable of easily riding on just about anything I can think of, and using judgement for walking through perhaps an extremely rocky (frame damaging rocky I mean) short section would be always doable.
only you know what you are considering riding on, but I can't imagine it's predominantly hard core mtb descent stuff or deep sand all the time.
on that assumption, I'd gladly ride this fun bike with a moderate load with those tires, all the "regular gravel" stuff will be great.
tire pressures appropriately! For traction and easier body bouncing about.
cheers
I agree that wheel and tire selection is crucial and should be appropriate for the ground you'll encounter. The Diverge has a bit of front suspension so that's good, but the gearing might be a bit high for really "chuncky" terrain. but you could always change that. There are also lots of reviews on Youtube so have a look at those. Then take you bike out for some tests before you commit to a full on multiple day trip.