Multiselect option sets are a useful feature of CDS, but when you retrieve a record you get the numeric ID, not the text of the options. If you want the actual text of the options, this video shows how to build a flow that will retrieve them from the CDS Stringmap entity so that you can provide your users with a list of their selected options in an email or elsewhere.
This solution is on Github here: https://github.com/topness-msft/MultiSelectOptionSet
The Fetch XML I used here: https://github.com/topness-msft/MultiSelectOptionSet/blob/master/FetchXML
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