If my work schedule needs me to be at the office early in the morning and I can’t pray Shacharit during the ideal hours, may I wake up earlier (maybe an hour before sunrise or so) and davvven/tefillin/talit?
In this situation where you will not be able to pray in the proper time you may pray earlier.
There is no set number of minutes prior to sunrise because its all based on the time of year and sunrise. You can take a look at https://www.myzmanim.com where it will tell you the earliest time you may put on tefillin/talit.