I've ended up with both a Fenix 6X Sapphire, and a Fenix 6 Titanium Sapphire. Love them both. Fortunately I've kept my iOS to 13.1.2 and my Garmin Connect Mobile to 4.23. iOS 13.1.3 and/or GCM 4.24 have introduced syncing problems by many on the Garmin forums. Garmin is supposedly working on a fix for mid-November. Most units ship with firmware 3.0, and you'll want to disable automatic updates if you get one. I've avoided the iOS and Garmin updates, and both devices are working extremely well for me.
I really enjoy the Pulse Ox--which I'm using to monitor for sleep apnea. Also like respirations tracking, which is interesting. Found a watch face I love called "Data Lover", which if you pay 3 euros gives you weather updates every 15 mins including temp, wind speed and direction, and conditions, along with many customizable fields. It's been rock solid.
The F6X is great for activities with 8 data fields, and even the F6 with 6 fields is an improvement. Both have outstanding battery life in my case. I ordered a two pack of charging pucks from Amazon fo $8 I think, and they work well. I'm even using Garmin Coach to run a faster 5K after a 15 week plan and 4 runs per week.
I've put music on the Garmins for the first time, but you're limited to songs without DRM. Since I have Apple Music it's not ideal. Spotify works, but I've read about some recent Spotify syncing issues on the F6 series.
Edited to add: Ran for a little over an hour on Sunday with F6 and AW4, both starting from full charge. AW was playing music in addition to tracking run using Workouts. Garmin battery went down 2% and AW went down 23%. Garmin was connected to my Scosche HR strap, Garmin Tempe Sensor, Stryd Foot Pod (and on previous runs also the Plantronics headset) flawlessly the whole time.
Great devices despite some of the usual Garmin "beta" or "teething pains".