Make Pipenv create the virtualenv in the same folder

Try

PIPENV_VENV_IN_PROJECT=1 pipenv sync -d

This maybe helps someone else. I found another easy way to solve this!

Just make an empty folder inside your project and name it .venv and pipenv will use this folder.

PIPENV_VENV_IN_PROJECT is an environment variable, just set it (the value doesn't matter, but must not be empty). Make sure to export it so child processes of the shell can see it:

export PIPENV_VENV_IN_PROJECT=1

This causes the virtualenv to be created in the .venv directory next to the Pipfile file. Use unset PIPENV_VENV_IN_PROJECT to remove the option again.

You may want to see if the direnv project can be useful here. It'll set environment variables for you, automatically, when you enter your project directory, provided you created a .envrc file in the project directory and enabled the directory with direnv. You then can add any such export commands to that file.