Lee Garrett, writing for MyProductiveMac:

You aren’t limited to one search term. Once you’ve clicked on your first search element, continue typing and another list of potential search criteria will appear below. Click again, rinse, repeat as often as necessary.

Search in Mail on macOS has always been a bit of a chore to me. If you want to up your game in Mail, there are several good tips in this post. In addition to the one above, the post covers the use of natural language, boolean operators, and saved searches.