It’s not just hypoxia. Exposure of the vascular endothelium basement membrane is very thrombogenic. I do believe that is where the whole thing starts. As it progresses microemboli become strands of clot/. So that’s what you see in the lungs. One of the functions of the lungs is to filter emboli. And that’s what they see int the lungs. Strands of clot. Pulmonary tissue that has been savaged by direct viral attack. Loss of Type I and II pneumocytes do to direct viral attack. It’s exactly what they are describing in the CTs and on the posts. It’s a lot more than just hypoxia.
Frankly I doubt RBCs are much involved. So a virus binds to it and inserts it’s genome? Then what? Nothing is what. RBCs can’t process a viral genome.
Or being savaged by loose iron ions, freed by the virus attacking blood cells. The blood then loses the ability to hold oxygen and other organs starve.