How can I use a Bitbucket Pipeline to open a new Bitbucket Pull Request for the same repo?

I have a pipeline defined in the branches section triggered by certain branches. I would also like it to be manually triggerable, with a variable that configures execution in a certain way. In case of an automatic run from branches (where I can’t specify the variable manually) I would like the variable to be undefined or have a default value.
However, when I add a variables inside branches I am getting a 'Pipeline variables are only supported on custom pipelines' validation error.

I’m trying to build a pipeline that will build a React project, and copy pass it in the `/target/ directory to the next step.

I need to dynamically set the trigger of a step to manual or automatic based on the value of an ENV VAR.

While running pipeline script, Once build gets successfully created, Below script push changes on bitbucket repo. It get fails saying below error

While running pipeline script, Once build gets successfully created, Below script push changes on bitbucket repo. It get fails saying below error

I have BitBucket Pipeline that runs Terraform,
so need to run builds sequentially – next build should wait for previous build to complete
How is it possible to set?

I am trying to a backup functionality before the deployment by creating folder with current dateTime, but I am facing error