I’d recommend a database-only backup and using rsync to move over everything else. Move a Discourse site to another VPS with rsync. You can also rsync over the ssl certs so you can get the new site up before you change DNS.
Here’s how I do it: Changing Digital Ocean droplets with doctl (resize, floating ip, rename, etc) - Howto - Literate Computing Dashboard
EDIT: Sorry. I can’t tell if you’ve solved your problem or what. If I’m reading correctly , the easiest thing to do is switch back to the default, versionless template and rebuild again.