my ISP changed me to a hitron cgnv5 modem, said equipment has the bridge mode option hidden
What exactly is your question? Are you looking for help with your modem or a router? Is openwrt running on the device you are asking about?
I used to use bridge mode on my ISP's modem before, so all the work was done by openwrt (rpi4b), but my ISP upgraded services and switched me to a new modem that doesn't have this option.
I’m still not understanding what your actual question is in this context.
easier my isp modem doesn't have "bridge mode" option what other options can i use i read that DMZ can be an option but it's not "pure"
then you should probable ask them if they can bridge it for you ?
yes, DMZ could work, too.
IP Passthrough works the same?
You will be best served if you ask your ISP or look on the internet for details about how to configure your modem. This forum is specifically focused on OpenWrt. Your modem, it appears, is not running OpenWrt, so this is not the best place to seek assistance for that device.
"IP Passthrough" is the same as "bridge mode". Your router's DHCP request should pass through the modem and receive an IP from the ISP's server instead. This may or may not be a true public IP.
The article you've linked talks about how to configure OpenWrt to handle a situation where bridge mode is not available.
It seemed you were trying to figure out how to configure your modem -- that type of information (beyond just the very basics/general information) comes from your ISP, modem manufacturer, or other sources that specialize in the modem itself.