The interactive Merge (Data Management Tools) of 2.9.0 is not working as expected.
The Field Map part will not automatically match the fields -- just one entry per field in the Source. The Refresh button does not help at all.
In 2.7.3 the field map of interactive Merge worked perfectly with the same input data (8 feature classes). The Source shows (8) entries per field -- though in dark mode the gray (8) is very hard to see!
Also, in 2.9.0 the field map matching worked perfectly by using arcpy.management.Merge() in the Python window.
