If not this again, what would be your ideas of the path forward for aviation?

All of the constraints you mentioned are the results of decades of optimization around the tube-shape aircraft design. Meaning the design has to be proven first. Infrastructure will adapt.

Also, I suspect the first application will be military, such as Next Generation Air-refueling System (NGAS):

https://www.twz.com/air-force-says-it-needs-more-survivable-...