if there's direct and purposeful attacks this would probably be beyond your scope. Cloudflare can help, depending on the type of attack. Cloudflare paid services might be a tad better, but depends on type of attack as well. I wouldn't rely too much on plugins/software on the site, that's like the last line of defense, if they're getting up to that point it's probably too late.
Hire a security team/individual to help address. Ask for references.
Otherwise talk to your host, they might have it as a service/additional feature perhaps or can send you to someone who can help so long as your not on EIG host.