Cerastez,
I agree with the others, what works for you is what matters. I have no perfect system, but I’ve tried some things, hope this helps..
When traveling domestically, I use a rolling Ciao bag from Costco (it can fit under some airline seats if necessary, but it goes in the overhead). My personal item is the RS Veloce bag, I love the backpack straps and the crossbody bag strap. It has the sleeve to fit over the handle of the rolling bag. I love it so much, I gave one to my sister, but she said there are too many pockets!
But I don’t do rolling bags overseas, I prefer backpacks so I can have both hands free.
Overseas I always do carry-on bags, always backpacks, no checked luggage. Each time I bring less stuff. No rolling bag, just 40 liter backpack that goes in overhead. For personal item I use a discontinued Monroza nylon shoulder bag that is self-stuffing, simple, I can zip my phone into a pocket, it holds little things.
I experimented on GAS tour and Best of Switzerland tour in 2019 using ultralight, self-stuffing G4Free 40L Lightweight Packable Hiking Backpack from Amazon. It costs $27, so it was a good buy. Inside that, I had my clothes packed inside a smaller G4free 20 liter pack that later became my day bag on the tour bus. I could carry rain gear, the day’s guide book pages, water bottles and lunch.
It suits many people to use such lightweight bags, but our trip was about a month and the drawbacks of such lightweight packs got irritating: 1. Water bottles fall out when backpack is set down because it’s formless. 2. Packing the backpack so the stuff inside didn’t poke me became annoying. 3. All the chocolate bars I was carrying home nearly overloaded the bag, stitching was starting to tear. 😁So, different strategy for our next trip.
I like having featherweight, yet sturdy, nylon bags as mentioned by several posters, because shops(grocery stores) generally don’t provide bags. One is coming with me again.
For museum days or city walks, I will use the Monroza purse. It doesn’t fit my rain gear but I can carry my sunglasses, phone and map or papers easily, eye drops, etc. I wear travel wallet on my waist, not in the purse.
I’m still pondering my day bag solution. I have a 24 liter Mountain Hardwear daypack, might be the answer. Whatever I decide to bring, my comfort will be a bigger consideration than in the past.
I hope you will update us about what you decide to do. BTW, your Baggalini bag looks great.