Yuo don't need to switch networks. What you need to get timely update direct from Samsung is to buy their unlock phones. I bought the s7 international version and got the july 1 patch as soon as it was released by samsung. Pricey not really but you dont need to stress on security patch or updates.
I'm using it and haven't experience any issues.
If you really need total compatibility you can always get the USA unlocked version.
Which I'm pretty sure will have the bands your looking for.
Then make a choice you want VoLTE or you want a phone that will get latest patch as soon as it comes.
You will also not get all features (VoLTE, etc) if you purchase a non Rogers branded phone.
I have the G935U (American unlocked version) and it's only sitting on the May security patch...carrier features such as voLTE and voWIFI aren't working with Rogers since it is not a Rogers IMEI.
To each his own. For me latest OS updates are important. As long as I can make calls, send txt and download is fast I don't care much bout voLTE.