I think the Diane is completely different from the Métis! If you live near a store you could go and try different options, because sometimes a bag seems perfect in our mind but trying it on could be completely different. You could try the Diane, Odeon, Neverfull, NeoNoe, Onthego, Speedy 20 or 25…Almost same ages here! 7 years and 8 month old. I like the Diane but worried it was to comparable to the pochette Métis
My son is 6 now, but when he was younger I always had a small crossbody bag for myself and carried his items in a separate bag attached to the stroller because I can’t carry heavy bags. That was very practical too.