"Generating Unique Values" symbology - classified for a Raster

[GeomaticsPublisher]

Can somebody please explain why you need to ArcGIS Pro now needs to "Generate Unique Values" in order to generate a classified symbology. Why can't we just specify our own values without having to wait for hours (if using a large image) to generate a classified symbology? I never ever use teh one suggested by Pro anyway!!

And another thing, you can't even apply a classified symbology to image services (e.g. Raw NDVI from Sentinel-2 views on living atlas). I suspect it is because of the Genetate Unique Values thing. Is it possible to remove this requirement to generate unique values? It never used to be a feature, why is it now? It certainly wasn't a problem in ArcMap 10.x (even with the living atlas layers. Productivity working with thresholding of greyscale images has plummeted with that feature.

[Robert_LeClair]

There is an ArcGIS Pro option you may want to consider.  On the Projects tab -> Raster and Imagery tab, in the Raster Dataset category, you'll see the "Maximum number of unique values to display"  By default, it's set to 65536.  You can update this value to anything you want, like 100 for example.  Then test to see if the time involved to create unique values is reduced.