You can perform the step in my last paragraph to make it work in those cases. It would come down to introducing 2 new build args, making sure the user you create sets the uid:gid based on these values, defaulting to 1000:1000 so it works for most but allows you to override them by modifying 2 env variables in an .env file (you can configure docker-compose to set the build args with env vars).

If someone has a case where they are doing anything you described the above steps can be implemented in like 5 lines of code and 5 minutes. I didn't add it to my example apps because there's only been 1 or 2 requests for it over multiple years and I've never encountered it once, no one taking my Docker courses has ever hit a road block by it either.