I’ve heard a lot of people with the same issues you’re having and they’re not able to go to 3G in a low 4G/LTE non 5G area. My niece had the same issue. Maybe if you call Rogers directly because from what I read it’s a carrier setting. The iPhone 12 can support 3G but Rogers has to enable it. I was going to upgrade until I found this bit of information. It’s just not Rogers, but other iPhone 12 users have the same problem. The only suggestion I can think of is that if you get a hotspot that connects to the Rogers extended network using 4G only and then you can just use your iPhone 12 off the Wi-Fi. It’s usually only $10 to add on to your plan and share your data. You also have 15 days to return it if it doesn’t work out for you. In my case on the hotspot, LTE didn’t work and was extremely slow, but 4G gave me full bars and decent speed. I still had to use the extended network though. I was in Port Maitland though, really rural my phone kept trying to roam on the American towers as well. If you figure out a way, let me know.
