>> However, many observers consider that the Iranian role has been exaggerated, taking a fairly distant supporting role at most, with the Houthis acting very much on their own agenda, rather than as an Iranian proxy. Overall, the evidence from SIPRI data, the UN panel, and other sources, appears to support the idea that, while Iranian arms supplies have not been trivial, the primary sources of arms from the Houthis has been local, from those sections of the Yemeni army that supported them, from their former pro-Saleh allies, captured weapons, and the sort of locally assembled equipment discussed above.
[#] https://sites.tufts.edu/reinventingpeace/2019/03/19/who-is-a...
Thanks to earlier post for the link
The implication from tufts is that this is not rebels firing missiles made elsewhere but assembling parts from global (dual use?) supply chains - which does rather imply drone / UAv manufacturing is within reach of any state and most groupings.