How to properly store non-opensource features for a project?

Question

git

Good afternoon.
There is an abstract OpenSource-project.
It has a commercial fork that includes features that should not be available in OpenSource. The fork is, of course, based on OpenSource code.
The code is written by one person, in the long run it can be a small (2-5 people) team.
What is the correct way to store these two codebases?
Should it be two separate repositories? How, then, to remember to commit common features both there and there, and not to commit commercial features in an open source repo?
Should it be two different branches in the same repository? How then to separate the prod, master and feature branches? How to confuse them?
Any other options?

Answer 1

Gitflow, for example. Don't forget about tags and cherry pick. Well, to make rules like in the master only through merge request to take only a certain code. Don't forget the documentation and Readme.md

Answer 2

As an option - 2 repos, the commercial one depends on open source