... then you should have said so from the start.
If no SIM Card is in the device, Wi-Fi region will be set to the region set by your display language.
If you're using "English (United States)" - no channel 12 and 13 for you. If you use "English (United Kingdom)" you will see both channels.
(You need to reboot after changing language for the Wi-Fi region to take effect)
I decided to fix channel 13 on the MI Max1 helium with no sim card, or bust.
It is still running EU 9.1.3, what I did was put in a sim card (roaming), flashed the latest global stable firmware, changed system language to UK English, and even after all that I had to reboot once or twice before I finally got channel 13.
Then I changed system language back to US English, put the phone in "airplane mode" with the sim card still in and running, toggled the wifi back on while still in airplane mode and channel 13 was still there.
Then I turned the phone off, removed the sim card, booted up - and channel 13 still works! with the phone still in "airplane mode".
Not sure if I really had to put in a sim card, but I couldn't get channel 13 before I did that.
But maybe I messed up something while trying without a sim card.
Not sure if I really had to flash the global stable firmware, but I couldn't get it to work with the original EU 9.1.3, and not with the global weekly 9.2.15 firmware either, which I tried flashing first.
We'll see how long it continues to work.