Yes, you can change the hex code your aircraft is broadcasting, but the FAA probably won't like that - they will want you to join the PIA program. https://www.faa.gov/nextgen/equipadsb/privacy/
All of which is clearly explained in under a page in Dotcom ID program I linked to. If you sign up for that program (which provides a third-party callsign assignment) and sign up for PIA and change the flight ID in your transponder, then you don't get tracking by N-number.
If you don't do all three of those things and keep transmitting your N-number via ADS-B, then you are trackable by N-number. That DCM2790 is using the same flight number for multiple legs and transmitting their N-number is evidence that they aren't maximizing privacy, not that privacy isn't possible.
Yes, you can change the hex code your aircraft is broadcasting, but the FAA probably won't like that - they will want you to join the PIA program. https://www.faa.gov/nextgen/equipadsb/privacy/