Concealment often serves as a means of leverage, to manipulate clients into compliance or negotiate higher fees. Moreover, this secrecy may mask subpar quality until the project's completion, leaving the client dissatisfied after payment.
I advocate for openness from the outset, making the final product accessible to the client from day one. This entails full disclosure of the whole process, including tickets, source code, contributors, pull requests, CI/CD pipelines, etc...
Delaying the unveiling of the project serves no logical purpose since you will ultimately receive the project regardless, you might as well always see it and look at what's happening in real time.
GitHub is used both project management and code storage platform, clients have access to the project since initiation, this access remains constant throughout the project's lifecycle.
To make communication within the project smoother, I restrict access to only one designated individual from the client's team.