Controversial opinion:
None of the “tests” the Creator gave Abraham abinu were pass/fail. Including the last “test.”
The directive given to him was phrased ambiguously, communicating only generally that he was to elevate his son as something wholly dedicated to the Creator. The purpose of the ambiguity was to allow an event to unfold that was to greatly impact both Abraham abinu and his son. An event, like the previous formative events in which the Creator placed him, in which he was called upon to develop deeper empathy and in which his sense of moral clarity had to correspondingly deepen, while also having to learn to let go of the ideas to which he’d become attached.
Note that Abraham abinu first acts based on what he believes to be the Creator’s direct instruction to him – but then desists from acting based only on what an angel says to him at a later moment. Note further the beautiful midrash in Pirqé deRibbi Eli’ezer, which says that the angel was truly the neshama of Yitshaq abinu.
In this way, we read of a God who does not make false demands of us, or try to trick us, or set us up for failure – but of a God who puts us in situations that even if we do not respond perfectly, still trigger something within us and bring us to greater perfection.