Using the identity \( \log_a b = \frac{1}{\log_b a} \), we get:
\[
\log_{e^{2000}} e^{2021} = \frac{2021}{2000},\quad \log_{e^{2021}} e^{2022} = \frac{2022}{2021}, \quad \log_{e^{2022}} e^{2023} = \frac{2023}{2022}, \quad \log_{e^{2023}} e^{2024} = \frac{2024}{2023}
\]
Multiplying all:
\[
\frac{2021}{2000} \cdot \frac{2022}{2021} \cdot \frac{2023}{2022} \cdot \frac{2024}{2023} = \frac{2024}{2000}
\]
Now, take \( \log_{\frac{2024}{2000}} 1 = 0 \)