My primary device is the iPhone 13 Pro. While I've gone back and forth between Android and iOS over the years, I'm firmly planted with iOS as my The iPhone is my primary device these days due to my reliance upon the Apple Watch, AirPods Pro and some casual usage of the Apple Card with Apple Pay (usually in coffee shops, stores and taxis).
Google Fi is my wireless carrier of choice, having switched after more than decade on AT&T. I have now been using Google Fi for 4 years and now use it with 2 phone numbers (on a group plan with two Google accounts of mine) and a data-only SIM for when I used it with my Thinkpad X1 Carbon.
I love Google Fi for a few reasons. First, it's just a super easy to use mobile carrier and since it uses your Google account you get great security off the bat since your Google account can be locked down with two-factor auth, security keys and Google's Advanced Protection Program. Second, it works virtually everywhere internationally with no change in price. And finally, the billing is flexible and easy to understand: just $10 per GB. They recently added new $70 per month unlimited plans ("unlimited" until you reach 22GB) which I moved to as I always consume enough gigabytes per month for it to be more cost efficient for me.
That's the general gist but there's more to it, like automatic network switching and automatic VPN if you're on Android. Here's my referral code if you want to give it a try and get $20 of credit. I have sucessfully used Fi on recent trips: New Zealand, Greece, Cayman Islands, Rwanda, Tanzania, the Netherlands and the UK.