https://www.w3.org/WAI/ARIA/apg/patterns/feed/examples/feed/

Recommendations for lists require to use arrow keys, home and end keys and optionally "type ahead" to efficiently navigate among list items.
Lists gain focus with a single TAB key and often also loose focus on use of the TAB key. Additionally the list may also offer group skipping.
See keyboard best practices. https://www.w3.org/WAI/ARIA/apg/practices/keyboard-interface/

The sample does use of the recommended keystrokes, instead the user has to press TAB many times to get from one item to the next (with an invisible stop where the focus is not visible, which does not conform to WCAG2.2 2.4.7 Focus visible).