Bell offers 5G coverage in all the major urban areas around Canada, but rural coverage is not there yet. Alberta has the best coverage of all the provinces. If you live outside the city, then it's best to stay with a 4G device for now.
In 2020 Bell partnered with Telus to bring cell signal to even remote areas of Canada. Together they deployed twice the amount of 5G towers as Rogers. Low frequency 5G is in the pipeline, which will bring signal to hard-to-reach places like inside buildings and the Northern Territories.
As with every other Canadian carrier, Bell will be dropping its 3G network in December of 2025. M2M and IoT devices will have to move on to the 4G network. 4G promises to be around for a good long time, however. It's faster than 3G and can transfer more data. In the long run, 4G is a better network for both mobile devices and IoT devices than 3G.