google admob deprecated APIs

I'm currently implementing Ads for my Unity game and I am following google's documentation of integrating their admob api plugin with unity.

The problem is that when I import their api in my code, I get deprecation warnings. However, the documentation mentions nothing about it. The code works and I can see the test ads. The other problem is that the hello world project that they have linked in their documentation is different from their own documentation.

The "hello world" project uses the newer APIs (I think) but their documentation and tutorials use the old ones. I am confused here.

Which API should I use? Some of my other games use the old API. My question is, can I use the old APIs without any hassle instead of restructuring my entire codebase, since that is what is used in the documentation.

Here's the documentation that I am following.

https://developers.google.com/admob/unity/quick-start

https://developers.google.com/admob/unity/interstitial

Here's the hello world project that they have linked at the end of their doc

https://github.com/googleads/googleads-mobile-unity/tree/main/samples/HelloWorld

It seems the documentation has been changed and the new documentation accurately reflects the updated API that should be used.