It is one of those purchases that you can easily say "You get what you pay for". Yes, it is heavy and empty, sturdy and of good quality construction.
Every day for work I have a 25L bag with at least the Dell XPS13 and a Xiaomi Pad 6 PRO inside.

I bought this one because I am a gadget lover and I want to comfortably fit inside the aforementioned items as well as a drone, GoPro, possibly a DSLR, and various sticks, mounts, and gadgets. When it arrived, I did a test by adding various items and I took it, if I remember correctly, to 12 kilograms.

In practice, on the first trip by boat, I was at 9.8 kilograms.
I had seen on YouTube that the waist strap helps and it really makes a difference as you don't struggle so much during transport.

Also, the front point that makes it from 35 to 45LT has an indication for a tripod/selfie stick and easily fits "long pole sticks" (those that extend to 3-5m).
I put one of those there, a tripod for GoPro, and a floating hand grip for GoPro.

In August, it will likely exceed 12kg.
I also think that it might be a little difficult to fit under the front seat on an airplane, but in the overhead compartments, easily.

The bag is very sturdy and its construction is very good. It is a bit heavy even when empty, but you can adjust it inside to fit all your equipment or even clothes in many different ways. It has plenty of pockets and small compartments on the right and left side. It is comfortable on the back and shoulders and the material breathes. The front pocket is a bit of a hassle to open and close, but it's because of the interior zipper, which when fully opened, expands the bag from 35L to 45L.