Is it possible to register third party platforms in settings?

I’m really enjoying the way gradle’s versionCatalog works, but many third party vendors like AWS and Netflix’s DGS produce a pom bill of materials.

I know in my sub projects I can add:

dependencies {
     implementation(platform("software.amazon.awssdk:bom:2.20.135"))
     implementation("software.amazon.awssdk:s3")
}

I could even add the platform dependency in the root build.gradle.kts in a subprojects section, but in my projects I’m trying to get rid of even needing a root build.gradle.kts, so I’d prefer do something similar to what can be done with the version catalog:

dependencyResolutionManagement {
    repositories {
        mavenCentral()
    }
    
    versionCatalogs {
        create("libs") {
            from("info.offthecob.platform:catalog:1.0.10")
        }
    }
}

Does anyone know if it’s possible to import a BOM inside the settings.gradle.kts?

I could even add the platform dependency in the root build.gradle.kts in a subprojects section

You could, but you shouldn’t.
Practically any usage of subprojects { ... } is bad and should be avoided.
Instead you should use convention plugins to reuse build logic in multiple projects.

You probably could do in the settings script by using gradle.allprojects { ... } but also that is not really good practice.
As I said, better add it to a convention plugin you apply to the projects where it should be effective.