S1300 Guest Wifi in Access Point mode

I have an S1300, connected to my main router using ethernet cable. I was able to setup guest wifi in Router mode, in addition to normal Wifi. All is working fine at this point.
But I want to use it only as a Wifi Access point, not as a Router (my main router allready has DHCP).
When I changed the network mode in the admin panel of the S1300, it erased the Guest Wifi.
I can log in to the admin panel, but now it only shows one wifi network (for each band, 2G/5G).

Is it possible to use it as Access Point and still have Guest Wifi ?
Is this a bug or by design ?
I’m planning to use it in Mesh mode in the future ( I have two s1300 device, currently only using one).
I’m running on latest firmware version 3.102 (testing).


Does anyone have any ideas?
Is it supposed to work this way in Access Point mode?

You should be able to configure this in LuCI (the advanced configuration section) but I am not knowledgeable enough to tell you how to do it.