@RoyalPoisonator
Hey EldineVerhaal, hopefully this isn’t too late. I have also bought and attempted to use the Admob Blueprint Plugin for an app I’m working on. It was working fine on UE 5.1, I had to migrate to 5.4 because Google Play requires API level 34+ targeting. This is when I started getting the same Build error as you.
Explanation
Note that I don’t fully understand what’s going on exactly so my explanation may not be so good; As I see, there’s namespace error going on because two versions of the same code package or dependecy, namely com.google.android.gms:play-services-games, exist, v2:19.0.0 is the more recent one that gradle 7.5 has by default and tries to use (when enabling google play services support in the projects settings > android tab) and the older version 22.0.1
Solution
What worked for me (surprisingly) was to force the Admob Blueprint Plugin to use the newer version, the same one as gradle, I did this by editing its manifest file
Filename : GoogleAdmob_UPL.xml
Path : C:\Program Files\Epic Games\UE_5.4\Engine\Plugins\Marketplace\GoogleAdmobBlueprint\Source\GoogleAdmobBlueprint
I just changed the package version in the dependencies to match the one provided by gradle which is v2:19.0.0
I really hope this helps mate, cheers!