I went on April 6, 2024.
I've been there many times, and when I walked along the river towards Bamboo Forest Park, the crowds were less and I saw locals enjoying the cherry blossoms.
Although the cherry blossoms are only on one side, they are very beautiful and you can enjoy the cherry blossoms at your leisure.
If you're feeling energetic, it might be a good idea to get off one stop before the train and walk along the river to the festival venue.