If your average position is steady but clicks are down, the ranking is not the problem — what sits above the ranking is. The blue link moved down the screen even though it did not move down the results.
The new layer above you
A result page is not a static list any more. An AI overview, a set of expanded people-also-ask rows, a shopping strip — any of these can appear above the first organic result and push it below the fold. Your position report still says #3 because it counts organic slots only; it does not count the height of everything drawn before them.
That is why a chart can show a flat position line and a falling click line at the same time. Both are true. They are measuring different things.
No SEO work happening and traffic falling usually means the SERP changed around you, not that your page got worse. Verify against competitors: if they fell too, it's the market, not you.
What to do about it
Two moves. First, become the source the new layer quotes — state facts plainly so an AI overview cites you instead of talking over you. Second, chase the queries the overview does not answer well: specific, high-intent, local phrasings where a real page still wins the click. Holding your level while the whole SERP sinks is a win worth naming to a client.