How do I delete my group DSH, so I can get out of here?
Scroll down to the very bottom of that group's Settings page, then click the red Delete Group button on the lower right.
?Do this for each group you created (unless you've promoted someone else to own it).?
Also, unsubscribe yourself from any other groups you may have joined (such as this one).
?... and now I want to delete my account... which is not as easy as it is to get in here....
Click on your name on the upper right of any Groups.io page to drop-down the menu and select the Account item. Click the red Delete My Account button on the lower right.
That should pretty much do it.
If you've logged in to Groups.io with more than one email address then you'd need to do the above for each email address.