Please help

I have a 2019 cascadia dd15. Couple days ago out the blue as am driving the engine lost power and guages were zeroed. The truck completely lost engine power. After trying to restart the truck few times the ignition wasn’t even engaging. Waited few hours than it started with a check engine light and two codes showed (spn 520215 fmi 6 and spn 171 fmi 6). Drove with these codes for an entire day. The next day no codes showed up nor did it show check engine light. The same day went for an oil change at a TA and once the mechanic finished I cranked up the truck started fine than it lost engine power again and zeroed all the gauges with 18 different codes. Waited 30 minutes it started back up with the same two codes I previously mentioned. I tried driving while codes present but it kept losing engine power.
Please help me figure this dire situation.

 

Checked all the fuses it came back good except the fuse box in the firewall showed signs of corrosion. Turned on this morning few times but now it’s a deadbeat each time I try turning it on. Put it threw a computer earlier and dignostic report on hand.