Currently Vegas Pro still does not natively have the ability to automatically sync events to the beat of the music. Ideally, there should be this feature natively in Vegas. But while that is not possible, there are ways to get great results using other applications along with Vegas. Below are the main ways:
Method 1
Using Focus on Vegas Music Video Sync 2.1
https://www.focusonvegas.com/music-video-sync-v2/
Method 2
Using MixMeister BPM Analizer With VASST Marker Maker and VASST Still Motion or Vegasaur
https://mixmeister-bpm-analyzer.softonic.com.br/
http://vasstsoftware.com/product/markermaker/
http://vasstsoftware.com/product/stillmotion/
Method 3
Using Beat Edit in Adobe Premiere for export the bookmarks to Vegas and then I use Vegasaur to automate the events in the rhythm of the beats.