/set irc_hide_version on
Toggle hiding of VERSION reply.

/set net_throttle off

XChat doing periodic /who's can be disabled with Preferences → User list, and unchecking the Track the away status option.

/set gui_url_mod 0
/set gui_tweaks 192
/set net_reconnect_delay 300
/set gui_input_spell off
/set gui_lagometer 2
/set gui_throttlemeter 2

https://hexchat.github.io/
http://t0x.in/xchatsetvars.html