You may want to consider using SmartIRC library instead.
Might need a little massaging to work better in newer versions of PHP but it should still work
I might have a ircV3 parsing version of that still kicking about too
Or follow a more recent guide
It’s been a while since I did bots in PHP, I moved to node myself.
Initially I don’t see anything obvious wrong, but it’s been too long since I’ve been doing fun shit with sockets in PHP