ubnt has been the ubiquiti default login at least back to 2010 when I started using their products, before UniFi was a brand. I always assumed it was short for Ubiquiti Networks.
A lot of companies in that space did then. I was at a robotics company at the time and we experimented with mikrotik routerboards + the various long-range Ubiquiti wifi modules, some of which are even still listed on the website: https://techspecs.ui.com/uisp/accessory-tech/xr (though not the 900 MHz XR9, which was arguably one of the most interesting for long range comms)
This seems like an odd misunderstanding, especially because the correct inversion “UBNT” is the default login name for most UniFi web UIs.
You might have a bit of dyslexia, OP!