A simple and efficient way to deploy the instances from different branches in the same Github repo

In my development process, I frequently need to deploy instances from multiple branches within the same GitHub repository. However, I encounter a challenge when trying to switch between branches during deployment. Here's the typical scenario: 1. I initially deploy an instance from the main branch, and since there are numerous environment variables configured, I want to avoid creating separate instances for each branch. 2. To switch to a different branch, I disconnect the repository and then reconnect it, selecting the new branch. 3. Despite selecting the new branch and initiating a deployment, the system often defaults to deploying from the original main branch instead of the newly selected one. This workflow is inefficient and error-prone, as it doesn't reliably deploy the intended branch, and I'm looking for a better way to handle branch switching without losing the environment configurations or causing deployment issues. Thanks.