More crafty thieves will do a SIM swap first so the text message doesn't go to your phone but to their phone.

Low level phone retail workers are more than willing to sell your number so it can be SIM swapped.

The best alert system is a authentication app but so many banks don't use them.

For example if you sign into a your Google account on a friend's computer it will make you go into the YouTube app on your phone to confirm a secret number and that it is you.

Text messages can't be 100% relied on. Also you can inside your carriers settings set to lock you SIM but employees can still override that.

I also suggest turning on Push Notifications from the actual banking app in addition to text alerts.