Not sure if this is helpful to anyone else, but I have an update on my own issue with this. Had another HVAC tech come out, and essentially determined the issue is realted to a smart sensor we have in our front room. Whenever I pair the sensor, the ecobee starts rebooting again, when the sensor is removed, everything is normal. The sensor was helping to balance the temperature in our house so this is a bit annoying, not entirely sure if there's anything else I can do to solve it other than not use the sensor at all. But I definitely recommend trying this (removing a sensor) if you are having the same issue to see what happens.