1. Over a certain period, in the Google AdSense revenue report, the average revenue per click was approximately: US$1.55 (estimated revenue) / 30 (clicks) = US$0.05. See Figure 1.
2. Reference URL: https://www.shuijingwanwq.com/2021/08/04/5122/ . The most likely cause is the installation of the Yoast SEO plugin. I ultimately decided to disable it. See Figure 2.
3. After disabling it, over a period of the same length, in the Google AdSense revenue report, the average revenue per click was approximately: US$4.27 (estimated revenue) / 52 (clicks) = US$0.08. The average value in the report was US$0.14. See Figure 3.
4. It can be confirmed that the Yoast SEO plugin reduces revenue per click. Comparing Figure 1 and Figure 3, the page views were 506 and 403 respectively, and the impressions were 1103 and 1068 respectively, neither showing a significant difference. Although page views increased after installing the Yoast SEO plugin, overall ad revenue decreased. I ultimately decided not to enable it again.