Alternator or electrical?

2012 F150 Ecoboost: I recently had a light and message come on the
message board saying" low battery temporarily disabling functions" then a
red light battery came on. I got a new battery and drove it for five miles
when the battery light came on again. Next day I took it to get the battery
tested and also had the alternator tested. Battery was fine but alternator
was testing below 10. Ordered an alternator and had it installed. Drove fine
for almost 20 miles before battery light came on, then my power steering got
tough and turning was almost impossible. A bunch of lights came on and
blinked then went black and I had nothing. It was like a hit a wall. Battery
was dead. Jumped it and got it to a safe location before it died again. Can
not seem to figure out the issue. We have checked all fuses and grounds, it
seems like an electrical issue.