Parameter not getting reset to default value when clicked on "clear selection"

Hi anmoltripathi5 

The behavior you’re observing occurs because Power BI’s default behavior for clearing slicer selections resets to the minimum value of the slicer range when using range parameters. To make the slicer reset to a default value (like 0 in your case) instead of the minimum (-20), you need to employ a workaround since Power BI doesn't natively support this functionality.

Use this Dax:

Selected Value with Default =
IF(
ISFILTERED('YourTable'[Numeric Range Column]),
SELECTEDVALUE('YourTable'[Numeric Range Column]),
0
)

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
Happy to help!