Geez. I don’t remember the exact structure of the import- is it just a .json and you’re saying you have a 3.3 GB JSON file?
Are you using NGINX for your web server?
If so, with an import that large, I suspect NGINX is just rejecting it. Go to the NGINX config for your site (/etc/nginx/sites-enabled) and look for a line in the server block that says something like: “client_max_body_size 5M;”
Change it (and if it’s not there, add):
client_max_body_size 5G;
Then restart NGINX with sudo systemctl restart nginx.