I don't think you're allowed to redistribute them. Apple considers them system-provided assets, so you can only use them on systems that provide them.
> Availability of individual symbols and features varies based on the version of the system you’re targeting. When you export a symbol introduced in SF Symbols 2 as an SVG template and bundle it with your app, you can use it in apps that target iOS 13, Mac Catalyst 13, tvOS 13, or watchOS 6
> All SF Symbols shall be considered to be system-provided images as defined in the Xcode and Apple SDKs license agreements and are subject to the terms and conditions set forth therein.
https://developer.apple.com/design/human-interface-guideline...
Link to the sdk terms: