Good engagement and no sales is one of the most common complaints in marketing, and one of the most misdiagnosed. The instinct is always to blame the content. Often, the content isn't the problem at all.
Content that gets likes and shares is optimised to travel. Content that converts is optimised to make a specific person take a specific next step. Those aren't always the same piece of content, and a feed built entirely around the first will struggle at the second.
Reach and relevance aren't the same thing. It's possible to have real engagement from an audience that was never going to buy; students engaging with a B2B brand's content, for instance, or a broad audience discovering content that only makes sense to existing customers. Engagement from the wrong audience will never convert, no matter how good the content is.
A great post that leads to a slow-loading page, a confusing offer, or a five-field form is a conversion problem, not a content problem. Walk your own funnel from ad or post through to purchase and count how many places a genuinely interested person could reasonably give up.
Before rewriting the content plan, test the two things engagement can't tell you: who's actually being targeted, and what happens after someone clicks through. Those two changes usually move the number that matters more than a new content pillar ever will.