Repurpose a blog post into a LinkedIn post that doesn't read like a summary

Here's the blog post content or a detailed summary: A 1,400-word post arguing that most startups over-invest in onboarding flows before they have enough retained users to know what actually needs onboarding, with 3 supporting examples..
The single argument I want to lead with, if I already know it: You can't design onboarding for a retention problem you haven't diagnosed yet.
Blog URL, for your reference only — don't quote it in the post: https://example.com/blog/onboarding-before-retention.
Who I'm writing this LinkedIn version for: Early-stage founders and product leads obsessing over onboarding too early.

Do this in two steps:
1. Identify the ONE argument or insight in this post that's strong enough to carry a standalone LinkedIn post on its own — not a summary of every section. Tell me which one you picked and why the others didn't make the cut.
2. Rewrite it entirely in LinkedIn's native register: 1-2 sentence paragraphs with line breaks between them, no subheadings, no bullet-point dump of the blog's sections. Open with a hook line that has nothing to do with the blog's own headline — blog headlines are written for search intent, not for stopping a scroll.

Then answer honestly: should the blog link go in the post body, or should I hold it for the first comment instead? Explain the real tradeoff — native links may reduce on-platform reach because they pull attention off LinkedIn, but many creators now treat "link in first comment" as an unofficial workaround rather than a documented rule — don't state either option as a guaranteed algorithm fact.

End with a call to action that feels native to a LinkedIn post, not "read the full article here."