How to make it faster?

I have a site that outputs about 400 files when done, and I’m excluding the uploads folder (Media Library contents) as I have about 10,000 images (that I handle separately). The generation used to take like 3 minutes in a VMWare + PHP 7.4 + MariaDB + OpenLiteSpeed setup. Not fast, but I was relatively happy with it.

Now I’m in Windows 11 WSL2 Ubuntu 20.04 with Docker (not Docker Desktop), tried official WP image (with Apache and MySQL) PHP 7.4 and 8.1, PHP-FPM version behind Nginx, MariaDB, with and without WP-Cron, no matter what combination I tried, the same thing takes 10-20 minutes. Is there a hidden throttling/delay between requests to prevent abusing the server? Because looking at the CPU usage, it’s just chillin’ below 10% usage, like the script is not really trying to hammer the server (but it could take it). Loading a single page locally is under 200ms (it’s a fast handcoded site even without static – barely any plugins), and a few hundred of them with rejecting any links to images, and saving the files should still only take less than two minutes, especially when multithreaded (I understand this plugin doesn’t do that but regular static site generators that work from .md files probably do). Looking at the access log: it’s requesting a page every now and then like every second or so. Where is the bottleneck? I’ll try OpenLiteSpeed in Docker as a last resort…

Looking at the debug log, it’s full of lines containing my exclude keyword and determining that it’s “excludable”. Why are these even added to the queue/db?

If I change class-ss-fetch-urls-task.php to

foreach ( $urls as $url ) {
	if(stripos($url, 'myexcludeword') !== false){
		continue;
	}
	$this->set_url_found_on( $static_page, $url );
}

and basically apply my exclude filter before the URL is set for later processing in the database, it doesn’t say it is trying to fetch 10k+ pages/files at least, but it is still slow to save those 400 pages… just saved a few minutes.