If you really need a portfolio, I suggest:
* A classical project (CRUD for website, small cli, etc) * A not so classic project (choice is up to you) with documentation about the architecture, a clear API (rest for website, man page for cli, interface for library, and so on...)
Each project should be well tests covered, should have good automation (github actions are free for public repositories for instance) and easily run locally.
Bonus point if you can use language/libraries/framework from your future employer in a way that is correct but different from their usage. (Hard to know before)