Moving from WhatsApp to Signal is an important action, right now. WhatsApp’s parent company, Meta, has been involved in several cases of election interference: America in 2016, Trinidad and Tobago …
No. WhatsApp came first, but later adopted Signal's key exchange and encryption. WhatsApp was an independent company for years and had rejected several acquisition offers, but $19 billion is a big number.
One of WhatsApp's founders is now chairman of the Signal Foundation and a major financial backer of the project.