The bitnami image is probably on stable, so if you want to use it you’ll likely need to wait until the next stable release in 6-8 months. It’ll be lots easier to do a standard install, and unless you’ve got much more than a million page views/month, a single VM is probably Good Enough.
If you do want k8s you can use launcher to build an image that you run with k8s. ./launcher start-cmd will give you the settings you need to start the image.
Changing the domain name isn’t a big deal, as if you do a restore it’ll remap everything.
The bigger issue is to make sure that your backup includes the images and not links to them on the SAS S3 bucket.