Try using shadow conventions for now?

build-logic/src/main/kotlin/geyser.base-conventions.gradle.kts

@@ -37,7 +37,5 @@ publishing {
         groupId = project.group as String
         artifactId = project.name
         version = project.version as String
-
-        artifact(tasks["jar"])
     }
 }

build.gradle.kts

@@ -39,7 +39,7 @@ subprojects {
         when (this) {
             in platforms -> plugins.apply("geyser.platform-conventions")
             api -> plugins.apply("geyser.shadow-conventions")
-            else -> plugins.apply("geyser.base-conventions")
+            else -> plugins.apply("geyser.shadow-conventions")
         }
     }
 }