For context on why I'm opening this issue, please see https://make.wordpress.org/performance/handbook/performance-lab/version-support-policy/. Specifically, the following:

"The Performance Lab plugin commits to supporting the latest stable version of WordPress core."

Since we use some WP 6.4 functions see #1048 (comment), I propose changing the minimum WP version set to 6.4. This way, we won't need to handle safeguard or old version compatibility code.