Aswering my own question as I think I found the solution.
I had to update /etc/acpi/events/powerbtn
to this
event=button[ /]power
action=/usr/sbin/pm-suspend-hybrid
Then batocera-save-overlay
and reboot. Now the power button does suspend the handheld.
So either triggerhappy cannot override these commands, or there’s a bug in my multimedia_keys.conf
file.
But at least now I can have the handheld go in sleep mode :)