Hubitat used to include their Nest Integration in the firmware for quite a while after Nest essentially put their Developer Portal on hold. This of course led to a lot of users creating support cases... So, Hubitat pulled removed the manual installation option for their Nest integration from their firmware. Hopefully someday Nest will start accepting new integrations again some day. Until then, NST Manager works very well.
From what I have been reading, the now defunct official app isn't being actively maintained so the user app gives you a better service/experience. I've read users swapping to the user app. Nest is holding up Hubitat so until then we'll have to wait.
I have half my Nest devices on a normal account and half on a Field Test "FT" account which is a pre-release hardware/software channel (home.ft.nest.com vs home.nest.com) . Is there a way to connect this type account to Hubitat or preferably to connect both at the same time?
I also have many nest devices and have to instead integrate nest devices with homebridge. All Hubitat devices are also mirrored to homebridge. I then use Apple homekit app as my main dashboard app and set up any automation related to nest in HomeKit. This setup works very well for me, as hubitat’s own dashboard is always buggy for me when updating device state.