It’s done with a Google Timeline Chart. https://developers.google.com/chart/interactive/docs/gallery/timeline
I generally leave the Event Chart open on one screen and watch it fill in automagically as I dictate my events to Google Home.
Timestamps are down to the minute with the user interface but it’s possible to use seconds as well, though they don’t show up in the user interface. Reason being is EventLoggers is meant mostly for daily events and not micro data from IoT devices, for example.
Yes, eventloggers.com has fairly flexible csv export - you can export all events, or all instances of a specific type of event, or say, all events that are rated Very Good, etc.
As for bulk upload, I have a rough interface but it isn’t documented well and you need to know the id of each type of event. If you want to send me a sample csv, I’d be happy to see if I can get it working nicely.