It changes your perspective about the project a lot as you have to start caring about the entirety of the project, especially for such a big one like Meteor. In one way it is great because you can have a great impact on the project, but you have also to be careful not to overdo it to just suit what you want and be careful of your time. I have cough myself spending too much time coding on the project while not advancing other stuff that is important, personal and project wise.
As for creating a community around the project you mentioned, that is not something you can do. Community emerges out of people using it. You can only facilitate it by creating venues for the community to interact and get involved. If you are on GitHub for starters you can utilize GitHub Discussions on the project. If you have other active contributors you might want to choose some of them to become maintainers which will reduce the time you need to spend on maintaining the product. Since you are also freelancing you can then put your contact info in the product if people want to get paid support from you (pretty good thing I think).