Without prejudice
It doesn't mean what you think it means.
Without prejudice has a narrow, specific, litigation-related meaning. An offer to settle a dispute made “without prejudice” may not be presented to the court by the recipient to prove the sender admitted liability for the claim. That's all. It doesn't mean “notwithstanding anything to the contrary herein contained” or “without limitation”, or even “without affecting any other rights I might have now or at any time in the future”.
Sage lawyers, when they see someone use it in that way, will feel a flush of superiority. They won’t say anything — that would be vulgar — but you may be sure they're thinking it.