@Mechif, interesting. From what I read those settings usually have to do with getting the proper data icons to show. But yeah, change the country to CA and see what happens.
BTW, if you want to go further, operator code for Telus is TLS or tls. Sometimes upper or lower case makes a difference though not sure why.
Just for informational purposes (I couldn't/wouldn't recommend actually patching - unless feeling adventurous and have a full backup) is this article about GSM on CDMA/GLOBAL phones. LS990 is listed as a working phone.
https://www.internauta37.altervista.org/en/patch-fully-enable-gsm-cdma-global-phones-android
Here's an old 2015 thread about unlocking the LS990...
SIM UNLOCKING for LS990 ZV8| Sprint LG G3 - https://forum.xda-developers.com/sprint-lg-g3/general/sim-unlocking-ls990-zv8-t3083567
Some folks say you could probably just call Sprint, tell them the situation, and see if they'll unlock it for international use. I assume that info was/is probably for actual Sprint customers though.
LG G3 D851, crDroidAndroid v4.6 ROM, microG (NoGapps), MultiROM, XDA Legacy
Thanks Marc. I sent a PM to your XDA inbox on a different thought. I’m hoping we can carry over there for a moment.