Please check the format of your "Selected Parameter", if it is a text, try to use FORMAT function or Power Query to convert it to date.
If this can't help you get the desired result, please provide some sample data in your tables (exclude sensitive data) with Text format and your expected result with backend logic and special examples. It is better if you can share a simplified pbix file. Thank you.
Community Support Team _ xiaosun
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.