The Apple TV outputs at 60Hz unless you have manually lowered it in the settings. It does not automatically adjust based on the source like the Vero so I still think your TV may be the issue.
From Apple website - *If your TV doesn’t support HDR10 or Dolby Vision at 60Hz (50Hz in Europe), Apple TV 4K can use these formats at 30Hz (25Hz in Europe), but you’ll need to manually select a lower refresh rate in Settings > Video and Audio. Using lower refresh rates can result in poor performance, or choppy video when navigating on the home screen, within apps, or playing games. In these cases, Apple recommends lowering resolution to 1080p at 60Hz (50Hz in Europe) instead, and letting your television upscale to 4K. You will still be able to use HDR10 and Dolby Vision at these resolutions.