Resolve Unity AdMob Issues

I have a mobile game in Unity 2022.3.62f3 targeting Android. In a debug build every AdMob test ad appears, yet the moment I switch to a release build the ads disappear and Gradle occasionally complains about Google-play-services / Firebase version clashes.

Your task is to trace and fix the underlying dependency conflict, adjust any Gradle templates or External Dependency Resolver settings, and hand back a project that produces a clean release build (.aab) with ads reliably showing on a physical device.

Key facts
• Engine: Unity 2022.3.62f3
• Ad network: Google Mobile Ads SDK
• Current symptom: Ads not displaying in release, sporadic Gradle build errors
• Timeline: ASAP

Deliverable
– Updated Unity project that builds in both debug and release without errors
– Banner, interstitial and rewarded test ads loading in release mode
– Brief change log so I can replicate the fix on future versions

Acceptance criteria
1. Gradle completes successfully with no version-collision warnings.
2. Test ads appear in release on my device.
3. Google Play pre-launch report shows no new compliance issues.

I can supply the project via GitHub or zip and will test the final build immediately after your update.