Garmin is generally good but there are two issues:
1. Sleep and Hearth Rate tracking - it's still a bit hard for me to believe(am I missing something?) that Apple with Watch OS 9 seem to have much better sleep and hearth rate tracking (which Vo2max, HRV and other things are based on). Plus at least for me on Venu 2 watch GPS when running tend be really iffy , when running in small city with 5 floor buildings at most
2. App ecosystem - I don't really mind UX of Garmin it's ok for me. The issue is that I like to listen to podcasts and Garmins Spotify app is pretty bad at synchronisation. - The main app have bunch of things which are either useless (like insights), are often imprecise (Stress measurements) or are clumsy to use (setting up custom workouts through Web UI, strength training app) - I am bit capture by Apple now so I expect to get other marginal benefits with Apple - Access to data, there are only Apps integrating with Garmin and it's not really possible to create your own to have a full access to the API - garmin pay not as supported as apple pay in my area
The biggest challenge for me was always mainly the battery life and price to a degree - Ultra obviously doesn't really solve it. - I am hoping that annoyance of charging will be balanced out by more smooth experience - I don't like to wear my Garmin all day especially when just sitting behind the pc (maybe I just need a different band?) so charging might not be such a big deal, expect for travelling.
And as for a price I have same problem as I have with Fenix or Epix, I would pay for stuff I will never use. If only Apple Watch 8 would get the extra battery, battery GPS and extra button, but ou well.
So Apple would me to - get more of my runs without phone (thanks to apple pay, easy podcast sync, audible app) - more precise healthy tracking - bit better experience thanks to 3rd party and my reliance on Apple
or maybe I am just got convinced by marketing and try to justify it to my self :)