serve content of domain.com from otherdomain.com/folder/ without changing url in browser address bar

I am looking for a skilled developer who can help me serve the content of domain.com from otherdomain.com/folder/ without changing the URL in the browser address bar. I believe nginx reverse proxy is the most effective way to do that as x-frame is not what i want, I need the url to change according to the same architecture.

Purpose:
- The main purpose of this project is to maintain branding consistency.

Content:
- The content that needs to be served from the other domain includes both static and dynamic web content.

Hosting Environment:
- Ubuntu - Plesk - Wordpress

Ideal Skills and Experience:
- Experience in web development and server configuration.
- apache and nginx competence
- Familiarity with server-side programming languages such as PHP or Node.js.
- Knowledge of DNS and server configuration.
- Ability to work with both static and dynamic web content.

If you have the skills and experience necessary for this project, please submit your proposal.

Notes: I had add this to Additional nginx directives:
location / {
proxy_pass https://monbienetre.ma;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_read_timeout 60s;
proxy_connect_timeout 60s;
}
As you can guess it's not working I got error 500.

both website are based on wordpress, maybe wordpress is blocking it.