Recent national polling shows that young voters have soured on Biden, on Democrats and on voting in general. At the start of the 2020 primary process, they were not in Joe Biden's corner, but they came around (in a big way) on election day. Now, they seem to have reverted to their original assessment of the President. They also express frustration with the pace of change (or lack thereof) that they hoped for in a Biden Administration.
Interestingly, the issues that concern young voters are pretty much the same as the rest of the voting population: inflation, the economy, COVID-19. The inability to deal with high gas and food prices affects everyone—not just those over 30. Just five months remain until election day, and time is running out for Democrats to show progress on solving these issues. If young voters don't see that progress, it will likely deepen their political ennui and result in a massive Republican win in November.