As you mention, upgrading the base components of a stack requires to install a newer version of the stack and migrate the data of the old installation to the new one.
Please note that all Bitnami native installers are completely self-contained and run independently of the rest of the software or libraries installed on your system. They won't interfere with any software already installed on your system, so everything you're already running will continue to work normally. That's why it's not easy to upgrade the stack on the fly and you need to perform the manual steps to migrate the app to the new installation.
You can also check our containers offering that allows the user to easily upgrade the base components of the different container.
We're working on adding more applications and base components to that library.