2015 MacBook Pro OS Recommendations
My 2015 MacBook Pro is running Catalina and I'm wondering if I should upgrade to Big Sur or Monterey or stay on my current OS for the best performance (as it's an older laptop)?
MacBook Pro 13″, macOS 10.15
Question marked as
Personally I would upgrade it to Monterey (the highest possible) and I wouldn't expect to see any performance difference (+ or -).
It will allow you to run the current version of Safari (better than an older version for security reasons) and/or will also allow you to run the latest versions of 3rd party internet browsers longer into the future when you can no longer run the current version of Safari.
If you decide to upgrade, backup first (recommended even when not upgrading). Also see: How to download macOS - Apple Support