According to me, dev tools should not allow us to change the source code and send request to just any website. It is a defect. This feature should be disabled.
The Dev tool should not allow us to edit the source code of any website because it causes prototype pollution. The person who uses the dev tool for any browser should be allowed to edit only the code of the website which he/she is developing.
For example, we can let the user edit code if the server is hosted locally while developing the website. Secondly we can use certificate key concepts where we can authorize a machine to edit the code for development purposes only. Other then that we should not allow the browser's user edit the code using dev tools to commit a cyber attack. This will make the code less vulnerable.