If a problematic bot is on any mainstream VPS it will just get shut down.

How would I shut down a bot on Digital Ocean making over a million requests a day?

Send an email to the Digitalocean abuse email with the time ranges and origin IPs.

I did this with OVH, never got any response.

abuse@ contacts never send responses (though some send acknowledgements) because they don't want to give any details about their abuse process.