The good faith clause does not apply to the condition I mentioned. Good faith applies to believing that the material in question infringes your copyright; it does not apply to believing that you actually own copyright on the allegedly infringing copyright.
17 USC §512 (c)(3)(A)(vi): A statement that the information in the notification is accurate, and under penalty of perjury, that the complaining party is authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.
You wrote "Filing a DMCA takedown notice for stuff you do not own copyright for is perjury" which is ambiguous -- does "stuff" mean the allegedly infringing artifact (not perjury), or the allegedly protected work (perjury)?
17 USC §512 (c)(3)(A)(vi): A statement that the information in the notification is accurate, and under penalty of perjury, that the complaining party is authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.