Bridging 2 wifis to one lan port

im using a TPLink TL-WA801ND v5 with openwrt for quite a while now as a bridge from my mobiles wifi to lan. The bridge is configured via relayd and is attached to a gateprotect firewall as the main uplink. But sometimes, i dont want or cant use my phone as wifi hotspot (like i need to have it in my local network or so), so i want to connect to another wifi as a backup uplink from the tplink. Is there a possible way to do it? When adding a second wifi and also bridge it, i cant even activate those changes, it just times out. Is there anything that i missed? I didnt find anything when googling, maybe im using the wrong procedure to connect/bridge 2 wifis, maybe it isnt even possible to connect to second wifi as backup, when the main one shuts down, when theres only one wifi interface. I dont want to use a second AP as a backup uplink, because that would cost some money and if it isnt nescessary, i would avoid that.

A wifi station can only connect to a single access point. You probably need to use something like "travelmate" to handle your needs.