I'd like to suggest an idea that might solve a deployment problem in large, complex applications with a high number of languages.
Allow the selection of which languages the system will use to build the code.
For example, before running the application, check in some variable/configuration which languages will be built in the application; this would make the build faster.
We have an application that currently has 5 languages configured and it takes a long time to run. After removing 4 languages, it became much faster, but the other languages are still needed.
This problem mainly affected us when we switched to the Mendix React version.
Good idea, we need this as well.