Hi
i'm using cap gi-5haxd2haxd .It's not possible for me to use mac access list or hide ssid. What is the solution to defending against attackers that try to connect wireless by brute force attack?
Is it possible to block attackers by firewall filter rules ?

Use WPA3 and you will be safe against this. Your device supports it. Just know, that old devices will not be able to connect anymore, but you can't have two things at once - compatibility with old insecure clients, and also security.

What is the solution to defending against attackers that try to connect wireless by brute force attack?

If they're using the same MAC on every attempt, you can write a simple script that analyzes log files and adds the offending mac address to the access list, based on the number of tries in recent X minutes.

If they're using randomized MACs, God help you.