With my mesh device (is that gen 2? not sure) I can use the Particle Workbench to write code and compile it all locally, without having it sent to the cloud, then program it via DFU mode. I only activated this device once, but because I had issues with the setup process (apparently the OnePlus 5 has known issues with setup), I couldn’t actually create a new mesh with it, so I just unclaimed it and started to try and do this all locally (so I haven’t really used the Particle Cloud stuff, including it’s mesh capabilities, but the requirements for this project mean I can’t use it anyway).
Gen 2 is Photon/Electron/P0/P1/ESeries/etc. Gen 3 is mesh Argon/Boron/Xenon. Gen 2 activation is a bit different because you don’t have to create a mesh network at the same time.
On Gen 3 you don’t need to create a mesh at the same time either - it prompts you for that when you are adding the device.