after each change run

/etc/init.d/network restart

dhcp (and NAT) on wanbr by default

/etc/config/network

https://openwrt.org/docs/guide-user/network/wifi/basic

by default wifi is disabled, so at least the disabled option needs to be changed

vi /etc/config/wireless

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'platform/soc/18000000.wifi'
        option channel '1'
        option band '2g'
        option htmode 'HE20'
        option disabled '1'
 
config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'
 
config wifi-device 'radio1'
        option type 'mac80211'
        option path 'platform/soc/18000000.wifi+1'
        option channel '36'
        option band '5g'
        option htmode 'HE80'
 
config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'psk2'
        option key 12345678

/etc/init.d/network restart

/etc/config/firewall

at the end of “config defaults” add

option flow_offloading '1'
option flow_offloading_hw '1'

maybe set

option input ACCEPT
option output ACCEPT
option forward ACCEPT