Not 2.5 inches; however, an old apple/android phone could be used w/o cell connection to act as a mini-display. Just make sure you get the correct OS version for the Hubitat phone app. You can then define a central dashboard with messages, house, thermostat, lock status and access to control devices and have Hubitat notify you on the device.
I see several new ones on Amazon (US) for < $50, one with a 4" display. Also small, 7" tablets (I know, no tablets).
That's what I do with my retired Android phones. If you're just using Hubitat dashboards, you don't even need to install the Hubitat app because the dashboards open with a browser. I also have Tasker app on my phone and phone is plugged into a smart plug. Then I can turn the smart plug off when the phone battery is fully charged and back on when battery is drained.
IIRC there was a scrolling LED digital display being discussed around here to display notifications a while back, I can't remember if it every really happened or not. Probably bigger than you want, though.
Anyone remember that?
Am I just (again!) making things up whole cloth to make myself seem useful?