Hi,

Is there a way to restrict a certain format for phone number input

No it use HTML validation, to do this you need to use a Text field type, in Text field type there is an option to choose a custom format

or split the field into two, one for country code and one for phone number?

You can create 2 Text field type for fill info only available in edit profile page.
in profile page you can show entire phone number with HTML Delimiter field type and Content Plugin:

({user phone_country_code}) {user phone_number}

so it show something like (39) 3784834598
Docs about HTML delimiter at: http://docs.easy-profile.com/index.php/article/html-delimiter-field-type
Docs about Content Plugin at: http://docs.easy-profile.com/index.php/article/content-plugin