There’s more to Sqlalchemy that meets the eye. for this course we are most interested in the ORM: You can learn about it here:
https://docs.sqlalchemy.org/en/13/orm/tutorial.html
It’s good to know one ORM well because it will make it easy to understand other ORMs down the line. ORMs aren’t a uniquely Python thing, they exist in other languages too.
If you want to go deeper into Sqlalchemy, take a look at this: