I receive 50 or more unwanted emails a day. Can I have ony mail from my contacts come throu

Have a look at how to create Mail rules: Use rules to manage emails you receive in Mail on Mac - Apple Support

But what you are describing is a "White List". White Lists are not a good method to restrict emails because you will not receive valid emails that you have not identified ahead of receipt.

Make a rule (or individual rules) that allow preferred emails through to the inbox, and all others directly to the trash.

Edit: I use Outlook, and this is how I can set it up if I want.

This translates to: if the incoming email matches any user address in my address book, it goes through. If it fails that only condition, it gets deleted.