Particles are indistinguishable, this means that the specific particles that make up a physical object (like a human) are not important, you could replace all of them with different particles, ship of Theseus style, and it would be the same object.
What makes an object unique then is the specific configuration of the particles that make up that object. This configuration is a form of information.
Fortunately, we already know how to transmit information at the speed of light; no new physics required. This then reduces the problem to transporting the ‘printer’. No generation ship required. You need something that harvests particles locally and can receive a stream of data with what to print. You can bootstrap this, send a tiny particle harvester/printer that can print a slightly larger printer, etc.
What makes an object unique then is the specific configuration of the particles that make up that object. This configuration is a form of information.
Fortunately, we already know how to transmit information at the speed of light; no new physics required. This then reduces the problem to transporting the ‘printer’. No generation ship required. You need something that harvests particles locally and can receive a stream of data with what to print. You can bootstrap this, send a tiny particle harvester/printer that can print a slightly larger printer, etc.