Apollo made the same discovery, using xray fluorescence.
Whether XRF or hyperspectral mapping, these only measure the surfaces of things and not the depths, and have no physical “grond truth” to determine scale factors or accuracy.
I think a core-drilling robot mission would settle the matter.
As for theusefulness of 18% ilmenite, we’d need to develop a vacuum process to reduce the oxides to metals and separate out the iron, then develop a vacuum process to fabricate Ti parts on the moon. Oh and no water can be used, in fact no aqueous processes at all can be used.
We found just putting footprints there and taking pictures to be pretty challenging.
Everything is impossible until someone does it for the first time.