One of the primary reasons why your outbound calls may appear as 'Scam likely' or 'Unknown caller' because your phone number isn't mapped to your name / business name.
Therefore, right after you purchase a phone number on Salesgear, get it registered on the FCC (Federal Communications Commission). This will help in recognizing your calls as legitimate and there are less chances of getting marked as spam.
Here are some best practices that you could follow to make sure your number is not getting marked scam as you start using it -
Make sure that you have a targeted list of contacts who would actually be interested in hearing from you.
Always have a purpose/ reason to why you are calling the contact. Ensure you provide the value needed.
Avoid making more calls from the same number in a day.
Ensure that you are not calling at odd hours. Check for the contact's timezone and plan your calls accordingly.
Maintain the list of contacts' phone numbers that don't respond to your calls or don't want to hear from you again so that you can avoid making calls to the same person again in the future.