Disable extra mouse buttons on 22.04 (Gnome)

[Colin Law]

I have a mouse with annoying extra buttons that I keep clicking by
accident.  With the help of
https://wiki.archlinux.org/title/libinput#Configuration I managed to
identify the buttons (using libinput and xinput) and can disable them
with the command
xinput set-button-map 7 1 2 3 4 5 6 7 0 0 10
So I want to run this on login.  If I put it in ~/.profile it does
have the desired effect, but only after I open a shell window, so I
deduce that that file is not run on the GUI login.  I can't work out
where to do this for the GUI login.  I tried .xinitrc and .xsessionrc
(neither of which existed) but that didn't do it.

The system appears to be using XWayland, but I don't know if that is
significant.

Can anyone suggest where I should do the mapping?

Colin L.