WordPress redirect loop on nginx + apache reverse proxy

Issue was caused by nginx serving example.com/index.php while WordPress was redirecting to example.com/, thus causing a redirect loop.

This is the working config I used to fixed the redirect loop:

server {
server_name example.com;
root /var/www/example.com;

index index.php;

listen 443 ssl;
ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

location / {
        try_files $uri @apache;
}

location ~[^?]*/$ { # proxy directories
        proxy_set_header X-Real-IP  $remote_addr;
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $host;
        proxy_pass http://127.0.0.1:8080;
}

location ~ \.php$ { # serve php files
        proxy_set_header X-Real-IP  $remote_addr;
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $host;
        proxy_pass http://127.0.0.1:8080;
}

location @apache { # used by location /
        proxy_set_header X-Real-IP  $remote_addr;
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $host;
        proxy_pass http://127.0.0.1:8080;
}

location ~ /\.ht { # Deny access to .htaccess, .htpassword 
        deny all;
}
}
server {
    listen 80;
    server_name _;
    return 301 https://$host$request_uri;
}

Another thread with more details.