These do come out of the box. The advantages listed above all come from the fact that HTTP/2 runs all traffic over a single multiplexed TCP connection, rather

These do come out of the box. The advantages listed above all come from the fact that HTTP/2 runs all traffic over a single multiplexed TCP connection, rather than HTTP/1.1, where clients are forced to open many independent TCP connections (because each is a single channel where responses must be returned sequentially, in the order they were requested, and so block one another). That happens totally automatically, there's nothing special you need to do to enable that. There are also other potential advantages once you look at push etc, but using TCP as it was meant to be used really does give you many advantages for free.