Can not upload the data. Error during data merging "Error: Can't use more than 1000 distinct event types"
There is a hard limit for Timeline. It is not possible to upload more than 1000 distinct event types at the same time.
You might need to split it into multiple CSV files and then upload them. ( The fields in the file should have less than 1000 unique values. ) You need to find a column that contains more than 1000 unique values.
To make it easier to find it use a filter for each column.