It is not new for the Magento developer to face an error or try out a new customized feature. However, experimenting with things in a live online store may cause a functional disorder.
To avoid this risk, developers tend to move a live Magento 2 website to a local server in order to try out new themes or a plugin and solve the major issue.
Have you tried to move your Magento 2 live store into a local server and faced an error that says:
Warning: SessionHandler::read():open failed: No such file or directory
Must check the solution to Warning: SessionHandler::read(): Magento 2 by visiting https://meetanshi.com/blog/solution-warning-session-handler-read-in-magento-2/