JavaScript Loading Priorities in Chrome: Be careful when considering <script async>. Today it is often used to indicate non-critical scripts, but is inconsistent in being loaded at low priority and executed at high priority.
decoding = "async" and loading = "lazy" are different ways of thinking, "How does the main thread work?" Therefore, due to the mechanism, they are not compatible even if they are written together. At present, when added, in Chrome, loading = "lazy" has priority.