How to stop Nginx redirect if HOST HEADER is incorrect

Question

I have been trying to solve this issue for quite awhile now. Bots are hitting my sites hard with INVALID HOST HEADERS and Nginx forwards these requests to Gunicorn/Django. I need to stop them at Nginx. I have tried every solution I can find on SO, and elsewhere, but none seem to work for my setup.

Nginx.conf:

upstream backend_server {
    server backend:8000;
}

upstream backend_asgi {
    server backend_asgi:8001;
}

server {
    listen 80;

    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    location ~* ^/(api|admin|static|v2) {
        return 301 https://$host$request_uri;
    }

    location / {
        return 301 https://$host$request_uri;
    }
}

server {
    listen 443 ssl;
    listen [::]:443 ssl;
    server_name example.site *.example.site;

    ssl_certificate /etc/letsencrypt/live/example.site/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.site/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

    location /ws/ {
        proxy_pass http://backend_asgi;

        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";

        proxy_redirect off;
        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-Host $server_name;
    }

    location ~ ^/v2(?:/(.*))?$ {
        root /usr/share/nginx/html;
        index index.html;
        try_files $uri $uri/ /v2/index.html =404;
    }

    location /backend_static/ {      
        alias /backend/assets/;
    }

    location /media/ {      
        alias /backend/media/;
    }

    location ~* ^/(api|admin) {
        proxy_pass http://backend_server$request_uri;
        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 $https;
        proxy_connect_timeout 360s;
        proxy_read_timeout 360s;
    }

    location / {
        proxy_pass http://backend_server$request_uri;
        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 $https;
        proxy_connect_timeout 360s;
        proxy_read_timeout 360s;
        # Set upload size for videos to be 500MB
        client_max_body_size 500M;
    }
}

What can i add to my Nginx configuration to stop invalid host headers, given that I have a wildcard subdomain and bots are also using HOST HEADERS w/ subdomains?