The GitLens VSCode extension for inline git blames can eat IDE performance in large repos. I was able to significant improve it by removing the extension and using VSCode built-ins to achieve the same functionality.
"git.blame.editorDecoration.enabled": true,
"git.blame.editorDecoration.template": "${authorName}, ${authorDateAgo} • ${subject} (${hashShort})",
"git.blame.statusBarItem.enabled": true,
"git.blame.statusBarItem.template": "${authorName} (${authorDateAgo}) ${subject}"