Hi Fernand,
The bots are a fact of life. You already know that, since you have been banning them from before you got your certs. They are getting to your site not because of the certs, but because they are just going to every IP address and probing. What's changed is that since you issued the certs, they now know the names. There is no link between the certificate and the IP address unless you created an IP certificate instead of a Domain certificate.
I'm curious as to why your domain name is a random string of 50 characters. A domain name is an easy-to-type name for humans so they don't need to know the IP address. If you are going to type the random hard-to-remember gibberish, you may as well type the IP address.
Best Regards,
Richard.