I tried import saved objects from ‘oryginal’ kibana, one time it was pack of 3 visualisations, another was single index, in both imports after some time of loading I am goting error:
Sorry, there was an error
The file could not be processed.
I have seen errors when attempting to import saved objects from newer versions of Elasticsearch/Kibana into an earlier version. The Elastic distribution of ES is currently at 7.6.2 while the OpenDistro is at 7.4.2. Could that be the issue you are running into?