Thank you for reporting a bug to Unity.
After reviewing the behavior, we've confirmed it aligns with the current design and intended use of the feature. Investigating the project, the Voxel Play package is generating a lot of mesh data that is allocating more than the set 2 GB max memory size for Web. There are two options to prevent OOM from occurring, which are to increase the maximum memory size to 4 GB (4096 MB) in the Player Settings for Web or set the Low Memory Mode setting in the Advanced section of the Voxel Play Environment component.
We will close this case as 'As Designed.' If you have feedback on how the feature could better meet your needs, please let us know - we value your input and consider it in future improvements.