I'm with you.
It bothers me when people are given sci fi on the hard spectrum but then debate 'how hard it really is' for the purpose of defining then diminishing the value of the material; feels very self congratulatory.
Everyone who praises the expanse's 'hardness' are just as aware that protomolecule is space magic.
Space magic has its place but the expanse also offers a level of hardness I appreciate outside the narrative elements requiring the space magic.
I think its an important discussion in any talk of scifi to point out where the lens is callibrated with regard to hardness resolution.
Turns "expanse is hard scifi" debate on its head by simply changing that statement to "I like the level of scifi hardness in the expanse".
My nephew was reading a book and a character in it built a metal detector out of a radio in a survival scenario.
Due to my interests my nephew asked me if it was possible; if 'he could do that'.
I explained that i suppose you could construct a device to detect eddy currents out of the components of a radio, but it would be so terrible and unreliable that itd fail to detect any metal in any meaningful survival sense.
My nephew was satisfied with the answer, he honestly was uninterested in if it would 'work' but rather 'how probable' it was.
You could tell he was inspired to learn more about the topics that subjectively could allow someone know how to do that regardless of its objective viability.
So, the story could have cut ahead to after its been magically built off screen or could magically source parts from the devices without the actual necessary base components to achieve the conversion ignoring the whole radio aspect or the character could reasonably source components that "magically" works well enough to allow their knowledge to save them (the level this story choose) or the character could sit down and read through a data sheet and spend screen time soldering components to pcbs then accept they wasted all that time, and narrative space, because its an untenable goal given what they have to work with.
I think there are arguments for each of these levels depending on the narrative's slated goals, and being accessible to a broader audience is an important one of these goals.
I feel the further you move down that hard ladder the smaller the audience becomes and leaves less of the 'fi' element of sci fi for you to work with narratively.
I love ben eater's 6502 series and find it extremely entertaining, but does anyone expect that level of detail in a sci fi television show? Is that the end goal of these hardness debates?
I simply appreciate where the Expanse chooses to push that line into the esoteric, and yes even in the other direction of space magic, while still remaining accessible to a broader audience allowing people with less technical knowledge to be inspired to pursue expanding their knowledge within those fields.