Open source software literally means that the source code is available to anyone. In GitHub, that just means that your repo is public rather than private. But your method technically doesn’t matter. You could publish to a forum if you wish. That’s still open source!
Free OSS just means that anyone is free to use and modify the source code for any purpose. The details are usually defined in a LICENSE file.
I feel like you’re really asking about the common practices and methods used in FOSS. Right? If so, that’s entirely up to you as the maintainer. As the project matures, you may attract other contributors which will in turn will motivate change to your tools and methods.
Start with what works for you. Model after similar projects if you wish. Adjust as change is needed.
Unfortunately, I’m not familiar with installing Bitwarden so I can only offer general advice.
Port conflicts happen at runtime, not when software is installed. In general, you should be able to install as much software as you’d like that all relies on port 443 but only run one at a time.
If you’re seeing port conflicts when installing Bitwarden, then I suspect that something is starting the app after the install is done. If this is right, then maybe you can disable the automatic start. Or maybe you can ignore the error at install time, then configure the app, then start it.