The best way to deal with this is to have a URL for the latest event that doesn't change. Something like: http://example.org/current/ (Or maybe even just http://example.org/) Then when you create a new event, you archive the pages for the previous event to a subdirectory.
For example, the 2022 event might still be coming up so you would move last year's pages to http://example.org/2021/ and create a link to it, maybe in the "archives" or "previous events" section of your site. If there are pages that are specific to that year's event you could redirect them.
Doing it this way concentrates all your rankings on the pages that matter the most: the new event. Search engines don't have to switch to indexing different pages every year. You will also get much better link juice from external links to your current event because all the links from previous years events will boost it.
This URL strategy is recommend by Google's John Mueller:
Doing it this way will help the generic URL to gain value over the years, while still allowing the older versions to be accessible if someone explicitly looks for them. Another advantage of this setup is that it’s trivial for folks to find and go to the current version.