Nginx reverse proxy an anderen nginx reverse proxy

http {
    server {
        listen 80;
        server_name *.domain1.de;
        return 301 https://$host$request_uri;
    }

    server {
        listen 80;
        server_name *.domain2.de;
        return 301 https://$host$request_uri;
    }

    server {
        listen 443 ssl;
        server_name *.domain1.de;

        ssl_certificate /path/to/certificate1.crt;
        ssl_certificate_key /path/to/privatekey1.key;
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers HIGH:!aNULL:!MD5;

        location / {
            proxy_pass http://sub1.domain1.de;
            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;
        }
    }

    server {
        listen 443 ssl;
        server_name *.domain2.de;

        ssl_certificate /path/to/certificate2.crt;
        ssl_certificate_key /path/to/privatekey2.key;
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers HIGH:!aNULL:!MD5;

        location / {
            proxy_pass http://sub1.domain2.de;
            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;
        }
    }
}