Chiming in to say I could not edit the baseUrl property at all using docker-compose. My setup is a turborepo project where one app has cypress tests, and the only way to run Cypress at all was to run it from the root of the project configured as a turbo command. From there, if I omit cypress.env.json files altogether, I can add the --config flag to the CMD and point the baseUrl to the host + port of the service dependency in docker-compose, by injecting it into the Dockerfile with a build arg.