The Loudness Radar meter was licensed from TC Electronic, but unfortunately was no longer available as an M1-compatible plugin. This has been replaced in newer releases and on M1 systems with the fully-native Loudness Meter effect, located in the Audio Effects > Special group.

The new Loudness Meter, while not displaying the trademarked sweeping radar view, continues to provide accurate Short-term, Integrated, and Momentary loudness measurements and True Peak detection based on the ITU BS.1770-3 standard. The measurement and display can be customized in the Settings tab, and the new effect comes with over a dozen presets for both general standards as well as destination-specific loudness requirements from platforms like YouTube, Netflix, or Spotify.

For the original radar meter, I'd recommend exploring TC Electronic's hardware-based Clarity meter which can be used with a VST/AU plugin or connected directly to your audio interface for constant, real-time measurement. For more information, please visit https://www.tcelectronic.com/product.html?modelCode=P0D9L

Edit: Thanks to Holger for the reminder. In a pinch, you can launch Audition under Rosetta mode which emulates the Intel environment and will run the Radar Loudness Meter. Performance under emulation is not as good, but it would enable you to access or teach the effect. To do this, open Finder and go to Applications/Adobe Premiere Pro 2022/ and right-click/command-click "Adobe Premiere Pro 2022.app" then select "Get Info." Check the box next to "Open using Rosetta" and launch Audition.