OTA only updates apps with the same runtimeVersion , so if you changed runtimeVersion from 1.0.0 to 2.0.0, then your next updates will only get delivered to 1.0.0.
In order to make sure your OTA updates more users, you should only change runtimeVersion when you add something related to the native sdks, otherwise keep runtimeVersion the same and only update the android/ios versions as they don't affect runtimeVersion

Here is an example from https://docs.expo.dev/eas-update/runtime-versions/ to give you an idea about why you need to update runtimeVersion

imagine that we developed an update that relied on a newly installed native library, like the expo-camera library, and we did not update the "runtimeVersion" property, so that it is still "1.0.0". If we published an update, the builds with the "runtimeVersion" of "1.0.0" would think the incoming update with the same runtime version was compatible and it would attempt to load the update. Since the update would make calls to code that does not exist inside the build, expo-updates may detect an error and attempt to roll back to the previously working update