Here is a tip up front. Try to avoid using a bluetooth connection to your phone for anything. If you want to install updates or Connect IQ applications, use a USB cable and Garmin Express on your PC.
Everything related to connecting to my phone has been a nightmare. My phone is an Android Pixel 6. Maybe their apps on an iPhone are better, I don't know. Pairing has always been an erratic business, and there are several apps (Connect, Messenger, Connect IQ, Explore) that do little to cooperate and may even conflict with one another.
The software on the device is OK, albeit clumsy. I did get into a bizarre issue where a main menu selection to start collecting activity data got reassigned to the compass window. This was resolved by a device reset, and that involved me in the nighmare of pairing and phone apps.
The Garmin Express app that runs on my Windows PC has solved some problems that none of the phone apps could solve. The best approach might be to ignore all of those phone apps (except Messenger, which provides important functionality), and rely on Explore to do updates and install accessories.
A last thing that I don't like. Garmin pushes updates when they feel like it and give you no choice about it. This is not how things are done in general in the computer world. Most companies make updates available, but let you decide when and if you want to install them.
Tom's backpacking pages / tom@mmto.org