Yeah, this is the absolute last thing I'd vibecode. This is one step above sending your LLM to represent you in front of a court when you're accused of murder.
Totally in agreement with you and the previous commenter. It's not a full re-write. I took an open source project (DocuSeal) and customized it for our needs
That said - Docusign has a moat because people are afraid (and CYA) by using them instead of anything else. To make an eSignature legal isn't really that complex, you just need hash based attribution, some timestamps and some ToS.
Replacing Docusign with something else is no where close to having an AI represent you in court