Does the Office365 phone, by default, come to Power Apps formatted as -
(###) ###-####
If no, will the following work to force the number to appear in this format in the Text Input (DataCardValue) field of a 'New' form -
(###) ###-####
Code for Text Input in 'New' form DataCardValue field -
Text(Value(Office365Users.UserProfile(User().Email.TelephoneNumber),"[$-en-US](###) ###-####)