When a user selects multiple choices on a flow screen, all the selected values are stored in a single variable. In order to loop through them, you have to convert them to a collection variable.
Although the official release notes of Spring ’22 are not available yet, here is a sneak peek at some of the new flow features that you can expect.
There is no out of the box undelete records operation in Salesforce Flow. However, it is possible to achieve this with an Invocable Apex action.