Renew/Change 4G IP (WAN) DWR-921

Hello everyone, I have a D-Link DWR-921 router with OpenWRT.

It uses its own integrated 4G modem and the internet works very well.
For various reasons I want to change Public IP every several hours. I do this by rebooting.

The router takes over 1 minute to reboot (almost 2-3 minutes), and I would like to do it faster using commands.

I tried ifdown wwan, sleep 30, ifup wwan but the IP still shows the same.

The trick of changing the MAC does not work, since it is 4G, a reboot of the router already changes it. I would like to make a function as "flight mode" of the mobile so that it changes the IP in a few seconds.

What I can do?

root@OpenWrt:~#  uci show network
network.loopback=interface
network.loopback.ifname='lo'
network.loopback.proto='static'
network.loopback.ipaddr='127.0.0.1'
network.loopback.netmask='255.0.0.0'
network.globals=globals
network.globals.ula_prefix='fd0c:137b:1714::/48'
network.lan=interface
network.lan.type='bridge'
network.lan.ifname='eth0.1'
network.lan.proto='static'
network.lan.netmask='255.255.255.0'
network.lan.ip6assign='60'
network.lan.ipaddr='192.168.3.1'
network.lan_eth0_1_dev=device
network.lan_eth0_1_dev.name='eth0.1'
network.lan_eth0_1_dev.macaddr='MYMAC'
network.wan=interface
network.wan.ifname='eth0.2'
network.wan.proto='dhcp'
network.wan_eth0_2_dev=device
network.wan_eth0_2_dev.name='eth0.2'
network.wan_eth0_2_dev.macaddr='MYMAC'
network.wan6=interface
network.wan6.ifname='eth0.2'
network.wan6.proto='dhcpv6'
network.@switch[0]=switch
network.@switch[0].name='switch0'
network.@switch[0].reset='1'
network.@switch[0].enable_vlan='1'
network.@switch_vlan[0]=switch_vlan
network.@switch_vlan[0].device='switch0'
network.@switch_vlan[0].vlan='1'
network.@switch_vlan[0].ports='0 1 2 3 6t'
network.@switch_vlan[1]=switch_vlan
network.@switch_vlan[1].device='switch0'
network.@switch_vlan[1].vlan='2'
network.@switch_vlan[1].ports='4 6t'
network.wwan=interface
network.wwan.apn='internet'
network.wwan.pincode='1234'
network.wwan.auto='1'
network.wwan.proto='qmi'
network.wwan.device='/dev/cdc-wdm0'

Thanks