No quarrel from me here on pretty much everything - it has gone from Spitfire to Flight Deck of Concorde - ie a few basic instruments to a few hundred dials.
If you view the “entity” as us software devs may call it, and go in to General Settings (the one half way down, right hand side, lest you choose the entity above in the hierarchy (ie, if looking at the Device, the left hand menu General Settings is actually for the Application), you will find a link in red that allows you to delete.
BIG HUGE WARNING:
If you delete a gateway or an application, you will NOT be able to reuse the ID due to database security restrictions. You can reuse the EUI.
I think the entering a device id where an application is being setup was a minor detour from reality as the same application → device hierarchy exists in v2 and it is a fundamental concept of LoRaWAN.
Things like which version of LoRaWAN, Join vs AppEUI, where to get one etc etc aren’t overly maker friendly. I have a stock of official EUI’s plus a random EUI generator from source code from this forum but it is a bit of a WTF moment that is almost unanswerable - putting all 00’s in just feels wrong. I’m not sure it makes any sense to ask for it for each & every device on an application, I’d not see a common use case where you want devices on an application to use different Join Servers - although some vendors do seem to provide unique AppEUI’s per device they ship - a bit of a waste.
As I have said on another thread where @clv has created a CLI script to add ABP devices, I have a couple of scripts in the works to ameliorate this and once I’ve got those up & running in the next week, we can all work on different devices profiles to make it a bit of a no-brainer.