Google has recently added the ability to add negative keywords on the account level. That has a few advantages:
The bottom line is that negatives at the the account level is definitely worth using because of all the reasons stated above. But it is worth it to check from time to time to make sure the negative keywords are still appropriate for all the campaigns
The picture above is for reference.
1. Go to Tools and Settings on the Google Ads header
2. Under “Shared Library” click on Negative keyword lists
Here you can add keywords on the account level.