You can disable the pin but disabling the pin does not remove the data they already collected and stored in the cloud. If you decide to never create a pin in the first place, a pin is generated for you and your data is still uploaded and stored in the cloud forever. see https://web.archive.org/web/20230616082821/https://old.reddi...

The data is avilable to anyone who brute forces the pin or uses an attack on SGX which has a history of being leaky.

Note that they have been refusing to update their privacy policy after adding all the cloud storage. The fact that they don't make it extremely clear where, when, and how they store such sensitive data in their privacy policy should tell you everything you need to know about how trustworthy they are. In fact, the very first line of the privacy policy says that the service is designed to never collect and store sensitive information which used to be true, but is now a lie.

It's a bad look for a service that advertises itself to whistleblowers, activists, and others whose lives and/or freedom depend on that information being safe. They should make it very clear to people what their risks are, but as it stands today Signal's website actually misleads them.