As of Spring ’21, there’s a new flow action that shows up if Surveys is enabled in your org, allowing you to use Flow to send your survey invitations:
This initial release only takes a single recipient user, so it isn’t optimal for mass sends. It’s great for things like reminder messages. Mass Sending via Flow is on the Survey team’s near-term roadmap.
Note the use of Custom Property Editors by the internal team to provide picklists, checkboxes and multi-column layout in the property editor here.