Why is 'Hey Siri' not responding to my voice on iPhone XS with iOS 18.4.1?

Go to Settings > Siri > Talk and Type to Siri > Turn off Listen for "Siri" or "Hey Siri," then turn it back on.

You will be asked to read a set of verbal prompts aloud which will help Siri recognize and understand your voice to respond to.

Kenny745 wrote:

Have done that many times

It's not just working

And other things that required microphone works

Like WhatsApp audio message

But Siri is not working

I don't know if resetting will fix this but I don't like the stress of setting up a device again

Have you tried a Forced Restart?

Force restart iPhone - Apple Support