You can go cheap and just get a roll of mechanics wire. Looks to me that you can put at least a dozen loops of wire to hold it together. Inspect it once a month and you can replace any broken loops with new wire.
The SS cable ties look sweet though, that’s the classy way to do it.
Presumably the tube that the clamp encircles needs to be attached to the tube directly above it. The clamp is also encircling that tube, but is obscured by the cloth. So the task is to secure the two tubes firmly together.
If this is the case, weld it. Take it off the vehicle and have it welded.
Why go to all that trouble and expense when a reliable (and reversible) fix can be done with U-bolt clamps in ten minutes for ten dollars?
I don’t know if you can get it anymore but I have used MetalSet A4 liquid welding compound (a sort of super epoxy you mix as you use it) with good results on saddlebag racks and I used it on the basket of an old Lambretta once. Put it a little thick and let it form a joint around the break. But I am not ruling our marine-style clamps either.
This, or some mending plates (Flat bars with holes in them) and bolts, or drill through the bars and screw the mending plates in.