It’s normal for a president’s approval rating to fluctuate throughout their time in office based on various factors such as economic conditions, major events, policy decisions, and other factors. Public opinion can shift quickly and frequently in the political landscape.
If various reports have suggested that Biden’s bump or edge in the polls has flatlined, this could be due to a variety of factors including current economic conditions, handling of the pandemic, policy decisions, etc.
However, interpreting polling data can be complex. Different polls use different methodologies, and the level of trust and accuracy in polls has been a point of contention in recent years.
Finally, election outcomes depend on many variables, not just approval ratings of a candidate. A significant time remains until the 2024 elections and the attitudes of voters can potentially change in that time.