Enablement package activates hidden features disabled in 21H1 and earlier releases, when you installed the latest CU's.
Unless you need 21H1 for a specific reason, skip ahead to 21H2. The jump from 21H1 to 21H2 is minor compared to 20 -> 21.
Dynamic Update is optional. If you always create an updated ISO before installing, there's no real benefit.
DU pauses Setup to download the latest SSU/LCU combination if your image is out of date. Also, it doesn't work if you have no networking.