It depends on your mileage inventory and maybe even expected future use. If you rarely fly UAL (sounds like 1-2 times a year which is rare for ft standards), then I’d save the $840. Once I torched 75k UAL miles on a $500 ticket because I knew I wouldn’t need the UAL miles. UAL redemption gets tricky and very hard to use for 3+ tickets.
Devaluation is standard so you might get less use out of 96k miles in the future.

have a fun trip!