First article, first reference therein contains meta-study with restrictive criteria and proper registration (much data out the window) and has this neat little caveat:
"No trial investigated ivermectin for prevention of infection or compared ivermectin to an intervention with proven efficacy."
Pierre Kory is probably the world's #1 proponent of ivermectin, and he admits that the efficacy of the substance is squared directly over prevention and immediate onset.
Alpha strain showed highest response to ivermectin, subsequent strains showed more resistance. As virulence increased, the window to allow ivermectin a chance to be effective required either prophylactic dosing or immediately upon first symptoms.
Any trial which observes mild to severe covid is missing the window almost entirely, and much of the trials were excluded, so there was no broad net to find even "arguable" efficacy with such a trial setup.
Regardless, it was not about proving efficacy. The authorities loved to present it that way, because they believe they had a silver tool in a vaccine, but that never materialized, as all vaccinated got covid as well. So, a vaccine it was not, but for so long it was argued that selection of a "placebo" was "harmful" because it allowed vaccine avoidance--a now known falsehood.