Ap without physical wps button on (connecting printer)

Installing and Using OpenWrt
10

If you have installed the full wpad (instead of wpad-mini) and you have the hostpd-utils installed you have WPS support.

You can then launch the WPS push button action from SSH console with
hostapd_cli -i wlan1 wps_pbc

(Tailor that to your interface name)

Relevent commands examples and discussion e.g. in

And you naturally also need the WPS pushbutton action enabled in Luci config
See results in
https://forum.openwrt.org/search?q=Hostapd_cli%20wps

E.g.