I believe I have identified the issue. While debugging in VSCodium still results in the same error, the code executes successfully when run directly from another terminal within the Defold project or from the build folder. However, running the code from the VSCodium terminal produces the same error.
The problem appears to be related to the Flatpak version of VSCodium (the same issue occurs with the Flatpak version of Visual Studio Code). The sandboxing system used by Flatpak seems to prevent access to certain environment variables, libraries, or paths outside of the sandbox. This restriction is likely causing the libGLU.so.1 library to be unavailable, resulting in the error.