Use Nginx to run PHP and React side by side - php

Question

I'm relatively new to Docker, Nginx, etc. and have been searching for days for solutions but haven't found one. I'm transitioning from one stack to another so I need to keep existing functionality while refactoring. I'm trying to use Nginx to run PHP and React side by side where routes containing /php/ will display PHP and everything else will run React:
server {
server_name _;
listen 80;
root /var/www;
error_log /var/log/nginx/error.log;
access_log /var/log/nginx/access.log;
location /php/ {
#try_files $uri =404;
alias /var/www;
index index.php index.html;
try_files $uri $uri/ /index.php?q=$uri&$args;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass php:9000;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_path_info;
}
location / {
root /react-app;
try_files $uri $uri/ /index.html;
default_type "text/html";
#proxy_pass http://localhost:3000;
#proxy_http_version 1.1;
#proxy_set_header Upgrade $http_upgrade;
#proxy_set_header Connection 'upgrade';
#proxy_set_header Host $host;
#proxy_cache_bypass $http_upgrade;
}
}
I get forbidden errors and internal server errors constantly. Any ideas how to accomplish this?
Note: I run all of these containers locally without Nginx without a problem but because of how we have our servers set up (each container gets its own subdomain), when I put them on Portainer I need to configure Nginx.
Console error output