The Quick Setup is indeed gone under ROS7, but it is really simple to do an extender yourself.
You go to reset , select no config. And then do use a script like this:
/interface bridge
add name=bridge1
/interface wifi security
add authentication-types=wpa2-psk,wpa3-psk disable-pmkid=yes disabled=no name=YOUR-SECURITY-PROFILE passphrase=MY-PASSWORD
/interface wifi configuration
add disabled=no name=MY-CONFIG-NAME security=YOUR-SECURITY-PROFILE ssid=YOUR-SSID
/interface wifi
set [ find default-name=wifi1 ] configuration=MY-CONFIG-NAME configuration.mode=station-pseudobridge disabled=no name=2G_STA
/interface bridge port
add bridge=bridge1 interface=2G_STA
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=ether2
add bridge=bridge1 interface=ether3
add bridge=bridge1 interface=ether4
add bridge=bridge1 interface=ether5
/ip dhcp-client
add interface=bridge1
Once above done, your device should connect to any SSID you defined, and when you connect via ethernet, you can connect to it and have internet.
Now, if you want Wifi as well, it depends if your device is singe band or dual band.
If single band, you just go into the Wifi tab, add a slave Wifi interface. You configure it exactly the same as the 2G_STA. (add it to the bridge etc.) EXCEPT the mode is “AP” and not “STATION-PSEUDO-BRIDGE”
That way you have a simple Wifi range extender. From there you can add/adjust further…