I’m not sure I understand the difference between a dev container and a custom app dev container… And I feel like your tutorial is more about setting up erp next in a production environment isn’t it ?
By the way, I managed to get frappe running again by deleting the frappe-bench dir and then running the init script again. I then tried to follow this advice to push my work in my repo : I'm not able to ( git push) files in apps folder, at first it didn’t work because of what was in the repo. So i replaced the last command with a git push --force origin main and it did work with a few modifications I was even able to run the unit testing. Thanks a lot for your help.