Should I enable stealth mode?

If you activate that your device will no longer respond to ICMP, so these “test applications” as described there would think that your computer is currently unreachable (at least via the ICMP way).

I assume that it’s a setting for your local network?
If so, it’s not really necessary if you trust your local network, but also wouldn’t really hurt if you’re reachable via ICMP.
That always depends on your preferences and what you want to do.

It is not.
It is a setting on macOS. Ive change the ss. It is in firewall settings.

Here is an explanation about stealth mode.

If you’re concerned about security, you can use “stealth mode” to make it more difficult for hackers and malware to find your Mac. When stealth mode is on, your Mac doesn’t respond to either “ping” requests or connection attempts from a closed TCP or UDP network.

Is there other kind of application that would break bcuz of this?