For ultra light tripods it's super difficult to find a rigid solution.
I guess the weight issue is during transport therefore I suggest looking into how to transport the tripod in an ergonomic way, an appropriately padded strap for instance.
I understand. I have looked around and the Really Right Stuff TFC-14 MK2 Series1 Ultralight Carbon Fiber Tripod (47.2"), which weighs 2.47 lb / 1.12 kg is about the best I see. Even that has four sections, and I like three sections. It is expensive and I don't like that.
I have bought, but not received a copy of the Gitzo GIGT1545T Carbon Fiber Traveler Series 1
60.2” (8.6’) Weight 2.34 lb. It is four sections and probably not very sturdy. On that I might try the Ara-Swiss Monoball PO. I don't like the feel of it, but it is not too heavy and not bulky.
I see that these new mirrorless cameras have in-camera stabilization, but I feel that is laziness for my work. I like a sturdy tripod, a geared head (Cube), and so on. At the same time, since I am going to be 80 this year, I don't like to haul heavy equipment far... as I used to do. Your idea is a good one, make the hauling of heavier but more sturdy equipment less arduous by distributing the weight or buffering it somehow. No doubt I will try that.
In the meantime, I will play with these more spindly setups and see how that works out. And I am amazed at how good some of the new iPhone photos can be. For illustrative work, they are perfect to haul around. For my kind of photography, not so much.
All of this is just me fidgeting before the coming of spring. Meanwhile, I am all out of plants and it keeps snowing here... a lot.
So, I do still life... some. THis is the Nikon Z7 II with the Nikon Noct95 lens.