Is there another way to share my game without requiring users to download the App Inventor mobile app?

I've already tried with my game's installer file (.apk), but it's only valid for 2 hours.

You can package your app either as an APK to distribute it directly to other Android users, or you can package it as an Android App Bundle to publish it to the Google Play Store. More details on publishing via Google Play are available here: Uploading Your Apps to Google Play

Thanks for the useful feedback!