The 5G standard is a bit of a mess. In the US we heavily rolled out 5G NSA, which means you still have a 4G network core with both 4G and 5G radios at the edge. You get a chunk of the performance benefits without having to replace the network core first.

This usually has similar (in practice) performance characteristics to LTE Advanced.

5G SA is an actual, end to end 5G network. The two biggest wins here for an end user are reduced latency (a big focus in 5G) and reduced power usage (the phone doesn’t need a simultaneous 4G connection).