I want to confirm more information with you:
1.Does the issue occur while you click the excel file in SharePoint document library?
2.From your description, files whose file path exceeds the limit unable to be opened in office 2019, however can be opened in office 2016?
Generally, as long as the file path/name contains more than 218 characters, no matter which version, an error will occur.
To reduce the file path or name, use one of the following methods:
- Rename the file so that it has a shorter name.
- Rename one or more folders that contain the file so that they have shorter names.
- Move the file to a folder with a shorter path name.
3.Download a copy of the file and open the file locally to compare the results.
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