I use the RutOS app in my camper to connect to external Wifi or guest networks at campsites. However, the router uses mobile data from my mobile subscription.
In your WAN Interfaces, is your wifi uplink prioritized over and above all your mobile connections?
If not, change it by grabbing the handle (circled in red) and dragging the interface to the correct position.
Your WiFi as WAN interface may be named as the default ‘wifi1’ - I changed the name in my setup to ‘WiFi_Uplink’ to be more representative of its function.
If you are using Multi AP to connect to WiFi as a WAN, then step by step instructions can be found on my dropbox here, as a pdf.
I can,t priority my Wifi up and above my mobile connections with IPhone or iPad, only with my PC. Is that correct?
Maybe someone else can give a view, as I stopped using Apple kit years ago.