Hello ErikPLS,
Welcome to the community!
I understand you are still in Canada. Even though you have not left the Country, your device might show roaming when it connects to another provider's network as extended coverage (Fido-EXT). In order to use data in extended coverage, you will need to enable roaming data. There would be no additional charges for usage in extended coverage areas. If you live near a border, you would need to ensure your device does not connect to a US cellular tower. In that case, usage would be considered US roaming and incur roaming charges. Note that the roaming data setting does not prevent roaming for voice and messages. If connected to a US cellular tower, roaming usage could occur despite that setting disabled.
I also understand you are not that far from your house. The only criteria is that you device is unable to access Fido/Rogers coverage, but within another provider's coverage. The roaming agreements allow a different mobile provider's customers to temporarily use their networks as a courtesy. I have recounted this story before but it illustrates the point. We regularly visit Port Elgin, ON. Where we stay, on one side of the main street, we connect to Fido. However, on the other side of the street our devices connect to Fido-EXT. It's only a couple of metres, but it's enough to for Fido/Rogers coverage to be unreachable on our devices on that side of the street. That is just the nature of cellular service.
Adequate signal would depend, in part, on your location relative to the cellular towers. You can get an idea of your area cellular towers here. In addition to your proximity to the cellular towers, there are also many factors can affect cellular reception (see here and here). That's why no mobile provider can guarantee service. There are just too many factors beyond their control.
It should be noted that there are some limitations to extended coverage usage (ie majority of your usage needs to be your home network). If the majority of your usage is regularly using another provider's network (Fido-EXT), access to extended coverage would be restricted. As far as I am aware, a restriction would last 30 days (see here). However, repeatedly exceeding the limits would have lead to the service being blocked.
Unfortunately, if your circumstances don't allow for adequate Fido/Rogers cellular signal in areas you frequent regularly, there isn't much that can be done. It's a common misunderstanding that any mobile provider will suit everyone everywhere. That simply isn't the case. If you spend a good portion of time outside of a mobile provider's coverage, perhaps that mobile provider isn't the right one for you. As previously mentioned, the majority of your usage needs to be on your home network.
Hope this helps 😀
Cheers
