Continuing the discussion from Luci-app-sqm won't automatically start after boot:
Still the issue in OpenWrt 23.05.2, r23630-842932a63d
Adding this to /etc/init.d/sqm SQM is enabled in boot:
service_triggers()
{
procd_add_reload_trigger 'firewall' #<addthis
procd_add_reload_trigger "sqm"
}