Using a beta version of Dart can cause package incompatibility issues. Switching to the stable version will likely resolve these problems

If you’re still experiencing package-related errors, try switching to the stable Flutter channel and upgrading. Run the following commands:
flutter channel stable
flutter upgrade

What is the issue?

In IDX you are free to switch flutter and dart channels

You’re correct, it’s not a critical problem. However, I’d like to suggest that IDX should provide the latest stable version as the default, rather than a beta. I frequently find myself changing the default beta to a stable version when initiating new projects. This can lead to compatibility issues during development, where certain packages fail with the beta and require downgrades, subsequently impacting other packages. My concern is simply that a stable default would provide a more consistent and reliable development environment.