anyone know how to add delay/echo to a vocal track on latest garageband?

You can assign different vocal presets. If you created a Songwriter project (or most of the other types) you usually have a "Tracking Vocal" preset assigned to one of the tracks when the new project launches.

On the tool bar in the upper left you'll see a little circle that looks like a dial (it's near the question mark) the tool-tip identifies it as "Smart Controls" you need to click on that to enable the controls, then you'll have Reverb snd Echo controls along with a lot of other dials to turn to make your voice sound like you want it 😝 I recommend playing with the different presets. I'm a fan of the Tube Vocal preset. You can also add pitch correction if you'd like.