The Twitter app previously used to display a non-chronological timeline by default. Then a special button was introduced to change either algorithmically or chronologically and last year again they tried to be TikTok to display what they felt was of interest to users.
However, after being criticized, a few days later they returned the chronological timeline display. Recently, the Home and Latest tabs have been removed and replaced with For You and Following. The previous special button to switch between the two has also been removed as the default display is a TikTok-like For You, where the clips are not chronological and are what Twitter thinks the user is interested in.
While the Following tab is a chronological timeline and users need to scroll to the side to see this favorite timeline. For now, this change is only affecting iOS users and has not yet been distributed to Android users.
Twitter seems to really want to be TikTok, as it has previously also introduced a full-screen video display feature with non-stop scrolling up/down.