This is a placeholder for information regarding optimizing WordPress performance.
Lighthouse is the performance tool that everyone is using as a basis for benchmarking speed of websites. This tool is available from several websites which each have their own custom analysis and display of the results. The tool is also available as an npm package which may be installed locally and invoked from the CLI or it may be integrated in a node application.
This video is useful, but a bit dated regarding GTMetrix:
This Asset CleanUp: Page Speed Booster plugin is recommended and used extensively in the above video.
This article lists lazy-loading plugins.