How do I set up a static site + backend?

First time Linode user. I'm trying to set up a simple website, with pocketbase running as the backend on a linode and the static files being hosted on an object storage bucket. I also purchased a domain from google domains, let's say mydomain.dev
I would like to serve the website at myproject.mydomain.dev, while the backend should be reachable at backend.myproject.mydomain.dev

For the backend, I created an A record inside the mydomain.dev domain that points from the hostname "backend.myproject" to the IP of my linode. However, when launching pocketbase I get the following error: listen tcp: lookup backend.myproject.mydomain.dev on 139.162.133.5:53: no such host which looks to me like an error in identifying the address on the linode DNS.

For the website, I created a CNAME record with Hostname = "myproject" and "Aliases To" = "${storage_bucket_name}.eu-central-1.linodeobjects.com". Is this correct? Could I create a record with Hostname = '@' and just have a static site at the domain's URL?

Sorry for the stream of questions, but the setup of what I thought was a simple process hasn't been simple at all, and the guides didn't really help me out.