A migration to a new site (using the built-in migration toolset) is the only path here that is supported and will work. This will migrate most things, but not all so be prepared to either manually recreate some things or script their creation. This could be a good opportunity to adopt a DevOps approach to configuring the new site.
Things that don't migrate include client settings and RBA configuration although there are others. Basically, anything that didn't exist in ConfigMgr 2007 can't be migrated as the migration toolset was initially built for migrating off of 2007.