Note:This requires access to DNS records, an option to create subdomains or 2 separate domains, make sure You have that covered.
For production environments SSL is required, make sure Your backend domain / subdomain is protected with it, netlify makes it easy to maintain and free to use for the frontend part.
1.1. Backend DNS records pointing to wp server with subdomain & SSL easy managed via netlify or custom one. Example record for WP via netlify below.
AAAA 19.299.150.20 backend.yourdomain.com
1.2. Frontend DNS records – pointing to the netlify.app directory
Lorem ipsum…
2.1. .Backend DNS records
2.2. Frontend DNS records