running two rails apps on one server using unicorn, nginx. Only one app is showing for different server names

Question

sebastiandetering.com is my ruby on rails app.
I followed this guide to deploy my app with the mina gem rails-deployment-mina-guide_ralfebert.com.
I have https configured and it's been working since 2022.

Now I'm trying to run another rails app for my brother on the same server using http://juliandetering.com. (https later) http://juliandetering.com shows the same app as https://sebastiandetering.com, even though my upstream in nginx points to julsapp-live.

/etc/nginx/sites-enabled/julsapp-live

upstream julsapp-live {
    server unix:/home/julsapp-live/app/shared/unicorn.sock fail_timeout=0;
}

server {
    server_name juliandetering.com;

    root /home/julsapp-live/app/current/public;
      
    location /assets/  {
        gzip_static on; # serve pre-gzipped version
        expires 1M;
        add_header Cache-Control public;
    }

    
    location / {
        try_files $uri @app;
    }

    location @app {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $http_host;
        proxy_redirect off;
        proxy_pass http://julsapp-live;
    }

    listen 80;
}

server {
    listen 80;
    server_name www.juliandetering.com;
    return 301 http://juliandetering.com$request_uri;
}

/etc/nginx/sites-enabled/rails-demo

upstream rails-demo {
    server unix:/home/rails-demo/app/shared/unicorn.sock fail_timeout=0;
}

server {
    server_name www.sebastiandetering.com;

    root /home/rails-demo/app/current/public;
      
    location /assets/  {
        gzip_static on; # serve pre-gzipped version
        expires 1M;
        add_header Cache-Control public;
    }

    location / {
        try_files $uri @app;
    }

    location @app {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $http_host;
        proxy_redirect off;
        proxy_pass http://rails-demo;
    }

    listen 443 ssl; # managed by Certbot 
    listen [::]:443 ssl; # added by SebD 10/13/2022 to try to match peertube server conf
    ssl_certificate /etc/letsencrypt/live/sebastiandetering.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/sebastiandetering.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}

server {
    listen 80;
    server_name www.sebastiandetering.com;
    return 301 http://sebastiandetering.com$request_uri;
}

Both apps are working, here's the systemctl status for both apps.

root@vultr:~# systemctl status rails-demo
● rails-demo.service - rails-demo service
     Loaded: loaded (/etc/systemd/system/rails-demo.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2024-01-18 21:28:36 UTC; 3h 35min ago

root@vultr:~# systemctl status julsapp-live
● julsapp-live.service - julsapp-live service
     Loaded: loaded (/etc/systemd/system/julsapp-live.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2024-01-18 22:46:31 UTC; 2h 17min ago

I tested changing the root and proxy_pass of rails-demo in nginx to point to the julsapp-live upstream, and I saw the julsapp-live working as expected! Except now going to sebastiandetering.com would show julsapp-live.

How do I configure nginx such that julsapp-live is served when I go to juliandetering.com, and rails-demo when I go to sebastiandetering.com?