Every reporting cycle produces the same question: Search Console says 8,000 clicks, GA4 says 6,400 organic sessions, which one is right? Both are. They are measuring different things.
The four main gaps
Clicks are not sessions. A click is registered when someone clicks a result in Google. A session is registered when a page loads and the analytics tag fires. Anyone who leaves before the page renders is a click without a session.
Consent and blocking. Users who decline analytics consent, or who run a blocker, appear in Search Console and not in GA4. Depending on your audience and region, this alone can account for a double-digit percentage gap.
Session grouping. Two clicks from the same person within the same session window are two clicks and one session. Research-heavy queries produce a lot of this.
Redirects and canonicals. Search Console attributes the click to the canonical URL. GA4 records the URL that actually loaded. If a redirect sits between them, the two will not join on landing page.
What to do about it
Do not try to reconcile them to the row. Use each for what it is good at: Search Console for what happened in the search results, GA4 for what happened after arrival. Put them in separate sections of the report with a line stating what each measures.
Watch the ratio rather than the absolute gap. If organic sessions have historically been about eighty percent of clicks and that figure suddenly moves, something has changed on the site — a tag firing late, a new consent banner, a redirect introduced. The ratio is a useful health check precisely because the numbers never matched in the first place.