Is there a WordPress addon that is a “firewall” that blocks IP Addresses via a LoadBalancer X-Forwarded-For address?

I have a webserver that sits behind a load balancer which passes the X-Forwarded-For header. I need to block an IP address, eg. 1.2.3.4. However, the traffic is coming in from a Load Balancer, so I can’t simply block the IP, I have to block the XFF address.

Is there a WordPress plugin that will handle this for me? Something that maybe dynamically edits an .htaccess or otherwise WordPress internal file, whereas I can give the ACTUAL IP Address that needs blocking, and this plugin will handle the XFF record and block that IP versus failing due to only examining the loadbalancer IP?

I did some Googling but I couldn’t see any modern WordPress plugins that do that 1 simple thing: Block an/list IP addresses that comes in via XFF and not the direct (load balancer) IP.

Thanks!