Failure to publish a scene service from a scene layer package (SLPK) to the ArcGIS Enterprise portal occurs when the SLPK contains complex data and has more than 120,000 multipatch features.
There is no strict limit on the number of features when publishing a scene service from a scene layer package (SLPK) to the ArcGIS Enterprise portal. Instead, the complexity of the data affects the publishing process. Publishing large content may take time and sometimes fail due to factors such as publishing usage timeout.
Since ArcGIS Enterprise 10.8, the default publishing usage timeout has been increased to 12 hours. Issues related to publishing large content should be tested on version 10.8 or later. If problems persist, a new issue should be logged with specific details and data attached.
Please consider the latest guidance on how to approach publishing large scene layer packages.
Refer to the workflows described in this help topic for recommendations on how to publish large scene layer packages:
https://enterprise.arcgis.com/en/portal/latest/use/publish-scene-layer-ref-cache.htm
And refer to this blog post for guidance and advice:
https://www.esri.com/arcgis-blog/products/arcgis-enterprise/3d-gis/publishing-large-scene-layers-in-a-snap/
Note: This blog post states work is still in progress for the user experience but that work has been completed since then; the entire workflow can be done through the user experience.