As a long-time video and photography professional, I understand the need to transport gear in different configurations. You are not always going to need 5 lenses, lights and a drone, but there may be cases where you need all of those things.
For that reason, it is always good to have many options to transport these different configurations effectively, and with as little waste as possible.
Currently, I am shooting overseas (in the Philippines) for three months and this duffel/ backpack by Patagonia is my home while on the road.
Above you can see the whole shebang: 90 liters of duffel / backpack stuffed with gear for three entire months, and with plenty of interior space to spare! It took me a month of constant searching to find this particular bag by Patagonia. First of all, I didn't know that it existed, second of all, I didn't realize that this is what I really needed until I saw it in person.
Patagonia makes this bag in 60l, and 45l varieties as well, but I decided to go as large as possible knowing that under packing it would not be an issue.
As the contents of the bag are parted out, you can see that it basically breaks down into three categories: clothing, gear and a daypack.
The clothing is a revolving consortium of clean folded clothes in packing cubes, folded but unpacked pants, and dirty laundry in a dry sac.
The Eagle Creek packing cubes are a MUST for any traveler in my opinion. I have tried other brands, but very few seem to be as durable, lightweight and easy to pack. For example, the Amazon Elements bags that I bought for one third of the cost did not retain their shape and were a pain in the ass to pack. They also were significantly bulkier.
My dirty laundry goes in a 10 liter, airtight, ultralight dry bag by Outdoor Research. Sometimes wet, muddy, and smelly clothes must be transported along with everything else, so you are far better off if the bag is airtight. Many folks prefer equally lightweight mesh bags, not me. It also doubles as a... you guessed it, ultralight dry bag. There are plenty of cases where you need gear or clothes to be waterproof, and this does the trick.
The gear bag that I chose had to have several purposes; for starters, it had to fit and (somewhat) protect a drone. I REALLY wanted to try this configuration with a small, lighter weight, styrofoam shell, but because that container only has one purpose (carrying and protecting a drone) it would have been a waste of space. Instead, I opted for the WAY overpriced DJI bag by Manfrotto. At an absurd $325, this bag fits the drone, all its accessories, a 15" laptop, and my mirrorless camera gear with 2-3 lenses.
This bag is not only the majority of the volume/ weight of my pack, but it also gets pulled out and used as a carry on bag when flying, or riding on a bus/boat/van where the larger bag must be checked due to its size. All the expensive things go in here, and stay close to me at all times.
While this bag has plenty of internal and external pockets, it ranks fairly poorly in regards to secure-ability, mostly because the zippers don't have metal loops for locks. So far, it is still the best option that I have found for this purpose. In cases where I am not transporting a drone, I could probably suffice with just my daypack and a 30 liter duffel.
And lastly: the daypack. I pack it away empty, for ease of storage, and fill it as needed. This is a VERY important piece of travel gear to me because when the majority of my things are locked up in a hotel room, this is what I use to carry around my laptop, camera, money, or whatever else I need for a day at a coffee shop, or for a hike on the Andes.
It is rarely packed full, because I never typically use it for longer than several hours at a time. This 18 liter bag is made by REI and is super light weight, but very durable. It only has one external pocket. which I can clip shut for security.
There are some interior sleeves for sorting things if need be.
That’s basically it. Simple is better when traveling, but being prepared is vital. It took me years to become this efficient. You will get there as long as you keep shaving down the unnecessary items and get to a comfortable point.
When packed full, the duffel weighs about 18 kilos (40 pounds) which is a lot for most people to carry on their back for an extended period of time, but keep in mind this is only completely full when I am moving between hotels/ cities. It is not even completely full when I check it into a bus, boat or airline, as I carry the drone bag on with me. Also, I am as strong as an ox, haha. I can and have walked 6-8km in 90+ degree heat while wearing this thing at full weight. Not fun, but doable.
Best of luck, happy travels!