Truck is throwing emissions issues at me rapidly…how fast do they escalate until I can’t drive? P207F

2013 F350 6.7L

Two days ago I get my “Fill DEF, 500 miles to go” message. No big deal, will fill up next time I get the store. I drove no more than 10 miles since then and then the truck throws a check engine light (P207F), and 5 miles later I get a “In 50 miles, speed limited to 50mph. Exhaust fluid system fault” message.

Drove 1 mile home but I’m not where where to go from here. Both dealers near me are slammed and can’t see me for 2 weeks. Each are around 10 miles away. I found a local guy who says he can “try” on Friday but isn’t super confident, another 5 miles away.

Not really sure what to do. I need to at least drive the truck to the local guy to see what’s up; then home, then to a dealer. If I push close to 50 miles, how long will it take until the next “idle only” step? Can’t find anything concrete online, plus I’m a little worried at how fast things are escalating.

Anyone else have an error like this before?