Can’t get access to the Internet after Openwrt 23.05 firmware on GL-XE300 router

Hello. I installed the OpenWRT 23.05 firmware on my GL-XE300 router.
But after the update I lost internet. I also cannot enter the main
menu at 192.168.8.1. I only have access to 192.168.1.1. Can you tell
me what I need to do and how I can set up the Internet? It does not
work via ethernet cable and SIM card

This is expected.

Configuring the device depends on your isp and their requirements. Share more about your connection type and service provider, please.

https://openwrt.org/docs/guide-quick-start/start

I have a router from Xiaomi and the previous firmware was installed there without any problems. The Internet appeared on its own after installing OpenWrt

my ISP work through DHCP

You have another router connecting to the internet? If so, what is the purpose of this one in your network?

i mean that i have Xiaomi router and Openwrt works well from the begining it likes 19 version
but when i install Openwrt on my GL-XE300 it doesn't work
(i installed different versions)

What kind of internet service do you bavs? Cable modem? DSL? Fiber? Something else?

i don't know it's optical fiber cable go to my router and and after go to my computer. The problem is that everyhing works on GL-XE300 with 22.03 version. I also can’t access to the official GL-XE300 firmware via 192.168.8.1 when i installed 23.05 version

only access via 192.168.1.1

Weird that gsm light is on, i think you kept glinet config, and you need to reset openwrt to factory in safe mode.

Just to be clear, you replaced the GL-Inet firmware with official OpenWrt when you flashed it. It is one or the other, not both.

Then you have another router in front of this one?

From your screenshot, you have an IP address (10.0.250.175) on your OpenWrt wan. Internet access should work.

Have you tried it?

In my case on mi router 4a gigabit firmware 23.05.3 I changed the br-lan ip to 192.168.2.1 and apart from 192.168.1.1 I would get internet connection.