You could look at the http request headers and perhaps identify the scrapper script. You could also put a javascript challenge that is required to solve before pulling more data, and disable it for Google and Bing ips, so it's more work for them to pull data for some time.
Instead of simply blocking, you could detect them and do some kind of http slowloris response.
I'll try and find out and also I'll have to learn exactly what "slowloris" is. It may be helpful indeed!
It's usually targeted to webservers, before most HTTP servers got fixed you could DDOS a server with a tiny connection, but some HTTP clients can also be vulnerable.
But you may find better usage of your time than implementing this.
In this case though, to defeat scrapers maybe create some link which only the scraper sees and leave a "gzip-bomb"' like described here https://blog.haschek.at/2017/how-to-defend-your-website-with... and see how their scraper handle that :-)
Personally I just used a html-fuzzer to generate 5 MiB of junk html and named it wp-login.php :-) And a ssh-tarpit