There is an issue with the Libre 2 on Android version 14 phones at present.
In my experience using an Asus Zenphone 10 the phone will not always automatically reconnect to the sensor if the Bluetooth connection drops. Scanning the sensor (touching the phone to it) re-establishes the connection for me and it continues to work so long as my phone remains close by. Knowing a little about how Bluetooth works though I would suspect this might be a severe problem in crowded places, where interference from lots of nearby phones might cause the Bluetooth connection to drop even when the phone is close by, and then not reconnect automatically due to this issue. There are reports elsewhere online that the problem affects alarm functions (which I do not use) and is a constant headache for some people. Separately, there are many reports of Bluetooth issues with various kinds of devices such as earbuds after updating to Android 14.
If anyone is using the Libre 2 and is offered an update to Android version 14 I would suggest delaying the update until such time as Abbott or Google resolve the problem. If you don't always need live data or the alarms that depend on live data then Android 14 works okay in my experience, as the sensor stores data (I think 8 hours worth) and will send it to the app when it's scanned.