Performance issue occurs when rendering data containing more than 2000 records using a UniqueValueRender with a UniqueValueInfo created for each feature in ArcGIS Maps SDK for JavaScript version 4.27.
This issue is not reproducible using 3000+ uniqueValueInfos with this application: https://codepen.io/kekenes/pen/ExBeWaq?editors=100. If there is a performance issue, it may be hardware specific. UniqueValueRenderer is not designed for this use case. Cases where each feature may belong to its own unique value info must be handled using DictionaryRenderer.