I have been trying to get the number of days between two dates in google-sheet but sometimes it gives an integer and sometimes it gives another date. How to get only the integer?

Shared public sheet (sheet name DS): https://docs.google.com/spreadsheets/d/10NzbtJhQj4hQBnZXcmwise3bLBIAWrE0qwSus_bz7a0/edit#gid=517697699

Example

SN  COMPANY     AppliedDate     DaysSince   Today
-----------------------------------------------------------
2   McDonald    Feb 17, 2021    54              1   
3   Nielson Feb 17, 2021        Apr 20, 1900    2   **This should be number NOT date
4   Edelman Feb 17, 2021        111             3   
5   Upstart Feb 19, 2021        Apr 18, 1900    1   
6   Root Inc.   Feb 19, 2021    Apr 18, 1900    2   

Required

For the column DaysSince I would like to have only number. I want number between two dates but sometimes the same formula works sometimes does not work.

Is there any other methods to get number of days between two dates?