A dual wave gives you a lump of insulin up front, you choose how much, then delivers the rest of the calculated bolus over an amount of time, you choose how long, in drips.
An extended bolus - it delivers the whole lot in drips for whatever time you decide.
You can't program a pump to calculate a bolus, and deliver it eg half an hour later. Neither can you program it to give you some now, then none for half an hour, then the rest.
You'd have to do some of either of those manually.
Pumps are good - but they don't have the same capabilities as a human brain and hands and what capabilities they do have, they achieve differently!