"extremely inefficient" you say
https://youtu.be/OoJsPvmFixU "I Was SCARED To Say This To NASA... (But I said it anyway) - Smarter Every Day 293" reckons it"s inefficient, but Elon might be surprised of the conclusion ...
https://youtu.be/nxG0WAwwrGk "Smarter Every Day BOOST-ED!" could be of interest for people who want to emit critics on Artemis program based on Space X designs ...