With the release of the Garmin Enduro and the fact its in the same form factor as the fenix 6X you might find making this decision easier later on the year when they refresh the fenix line up.
If you can get a new/boxed Fenix 5X+ you would have a great watch, the 6 is pretty much identical aside from the larger screen and solar options.
For running the maps are fine and for cycling they are managable but if you are into triathlon long rides out you will be screaming out for a head-unit the first event you you do.
My timeline was:
Polar r800
Fenix 5X ( with Maps)
Wahoo Element bolt
Garmin 830 sold Bolt to fund most of it
Fenix 6X sold 5X to fund it. ( the only reason i upgraded was pulse OX, and larger nicer screen)
I generally dual record TR workouts using the wrist watch and the 830 lives on the outside bikes.
My training partner had the 945 and only upgraded to the Fenix 5X+ because he wanted something a little more flashy for his 60th I recharge mine every 5-7 Days.
Had issues with both fenix devices replaced easily through Garmin Support.
Garmin supports remote head units with certain models so you can record on the watch and stare at the data on the head unit. Some cheaper / older units might get you the best of both worlds within budget