Yes, you can tell Safari to render with faster refresh rates.
Oddly, Apple in 2024 is still not enabling this feature by default in Safari 18.0.1. You have to dig around in some hidden buried settings.
First, enable the Develop menu. Tick the box Safari > Settings > Advanced > Show features for web developers. Notice the extra menu in menu bar appears.
Second, choose Develop > Feature Flags. In the search bar of the Feature Flags window, type 60 to filter for the item Prefer Page Rendering Updates near 60fps. Untick the checkbox for that item.
Third, quit and open Safari.
Fourth, visit https://www.TestUFO.com/ to verify faster refresh rate.
You may see old comments about TestUFO.com not working with Safari or Macs.But that is not true nowadays. TestUFO.com works well. I tried that site before and after disabling this Feature Flag. And I tried that site on my MacBook Pro internal monitor with ProMotion as well as on my external BenQ monitor without ProMotion. The TestUFO.com worked as expected in all situations (if you reload the page).
Be aware that faster refresh rates do take more computer power, and therefore more electric power. If working while plugged in, you have plenty of electric power so not to worry. If working while unplugged, then your batter may drain a bit faster if you are using Safari extensively while in this mode.