Calculate Field taking hours to run with hosted feature layer in ArcGIS Pro

[McKenzieBredemeyer]

I am trying to run Calculate Field on a hosted feature layer with about 272,000 records and it is taking hours to even get to 15% completed. I have run Calculate Field on much larger datasets before stored on SQL servers or even just file geodatabases or shapefiles and Calculate Field would only take minutes to run. Is there something I need to do to make it run faster? I don't want to have to result to copying down the layer to a file geodatabase anytime I want to run Calculate Field and then throwing it back up to AGOL. I am using Python to run the Reclassify expression that is putting new values into an empty (but existing) field based on an existing field. ArcGIS Pro 3.3.

[DanPatterson]

Troubleshooting Performance Issues in ArcGIS Pro

probably focus on the data location suggestions and a few others.

There is no one solution, solution I suppose

[RTPL_AU]

@McKenzieBredemeyer 
Are you running the Calculate on the Attribute table or as a GP tool?  If as a GP tool, do you have the Attribute Table open?

I find in some cases having the Attribute Table open on the layer you are updating slows things down a lot. 

EDIT: With GP tool I am referring to the Calculate Field tool - you can still use Python etc. but not have the data in a map or the AT open.