Is P0171 System too lean enough to shut down a car?

Hey folks. I'm very grateful for this forum, and I've been reading all over the place, but have come to an impasse with my Prius. Wondering what i should try next.

Current Status:
Engine cuts on with heavy knocking sounds. After no more than 10 seconds it cuts off with message "Check Hybrid System"
The codes I've read are:
- P0171: System too lean - Bank 1
- P0301: Misfire - Cylinder 1
- P3190: Poor Engine Power

And after a few troubleshooting attempts (see below) I eventually see C1259 HV System Regenerative Malfunction.

What I've tried:
- Replaced spark plugs
- Replaced fuel injectors
- Cleaned Air intake manifold, throttle body, and EGR pipe (i wanted to clean the EGR valve but found it too difficult more to reach the "bolt from hell"). These didn't look overwhelmingly caked with carbon. Plus the code is that there's too much air, rather than not enough?
- Checked battery pack for damaged cells (all were ~8V)

Some context:
First observed by a family member on a random trip, i think they ended up driving it home entirely on the battery power, which may have hurt it. I got a grid charger and was able to bring it back up to ~212 volts, which seems to be enough? It's read as 3/4 full on start, but eventually dies out again. I'm thinking O'll need a new battery soon / now (thoughts on greenbean?) But what I'm seeing seems to be a gas issue right? I'll need to fix both eventually?

I want to try replacing the fuel pump next, but want to know if I'm on the right track. Does this combination of codes mean something else? Can a fuel pump just give out like that?

Thanks in advance

 

2010, 204k miles

No. I'll try this tomorrow, i gave it a glance and it looked fine


I ended up finding a used fuel pump pretty quickly and swapping it out. I also mixed in some injector cleaner to the fuel directly. Things seem better. Still rattling, still the same codes, but at least now it won't go into "Check Hybrid System" mode unless i drive it over 20 mph. I'm still surprised at those codes though and not sure what to do about them.