300,000 Miles - Triangle of Death w/TechStream Data

Hello Prius Chat, long time reader first time poster.

I have a 2nd Gen Prius 2008 (around 300,000 miles) that won't start unless the 12v battery is disconnected each time. Regular code readers won't pull any codes, so I managed to get TechStream running and got lots of codes! The combination meter is sadly usually dark but still comes on every once in a while.

First Triangle of Death (ToD): Started while parked and idling in a hot parking lot. The AC was on full blast with cold air, then notice the engine had turned off and was blowing warm air.

I've tested all the fuses I could find for continuity, haven't found any bad ones yet. The 12v battery is new and only a few months old.

The car will run after disconnecting and reconnecting the 12v battery but almost always pops the ToD after driving a bit.

The other day I noticed the ToD tripped while the car was just idling for a few minutes.

If my destination is less than 5 miles, not in stop and go traffic, and driving at steady pace, I can sometimes make it without tripping the ToD. Too many stops and the ToD pops much sooner.

I'm new to TechStream and only ran the Health Check. I haven't tried deleting any of the codes yet, figured I'd ask here first for advice.

Attached is the excel export from TechStream.

What do y'all think? Could the new 12v battery be causing all this? A friend has a 2006 Prius... I can try driving with a different 12v battery and see if the ToD pops. Will I need to clear the codes first?

Thanks!!

Hybrid Control
DTC Information 1 8/4/2024 1:56:43 PM
P0AA6 Hybrid Battery Voltage System Isolation Fault

ABS/VSC/TRAC
DTC Information 1 8/4/2024 1:57:42 PM
C1241 Low Battery Positive Voltage or Abnormally High Battery Positive Voltage
C1242 Open circuit in IG1/IG2 Power Source Circuit -
C1256 ACCumulator Low Pressure -
C1310 HV System Malfunction Freeze Frame Data
U0123 Lost Communication with Yaw Rate Sensor Module -
U0124 Lost Communication with Lateral Acceleration Sensor Module -
U0126 Lost Communication with Steering Angle Sensor Module -
U0293 Lost Communication with Hybrid Vehicle Control System -

Transmission Control
DTC Information 1 8/4/2024 1:58:47 PM
C2300 Actuator System Malfunction Freeze Frame Data
C2318 Low Voltage Error (Power Supply Malfunction)

Air Conditioner
DTC Information 1 8/4/2024 2:00:04 PM
B1421 Solar Sensor Circuit (Passenger Side) -
B1432 Air Inlet Damper Position Sensor Circuit -
B1433 Air Outlet Damper Position Sensor Circuit -
B1442 Air Inlet Damper Control Servomotor -

Gateway
DTC Information 1 8/4/2024 2:00:13 PM
B1271 Combination Meter ECU Communication Stop -

Occupant Detection
DTC Information 1 8/4/2024 2:00:27 PM
B1771 Passenger Side Buckle Switch Circuit -