Been sitting for months, HV battery suggestions?

I'm new to Prius and to the forums, although I have been reading a fair bit on here.

I bought a 2005 Prius with about 143k miles on a tow lot auction. It was sitting for about 4 months from tow till sale and no guess how long before the tow. I have 4 cells showing low charge voltages and higher internal resistance. DrPrius app battery tests says 5% battery life left. Is this more likely to be bad cells that need replacing, or corrosion from sitting for months not being used? Or are there other things that I should check first?

I tried to record the readings on the DrPrius app, but it gives me a file with a huge number of values for voltages and internal resistances. A typical line is
10.63,15.309998,15.290009,15.240021,13.890015,13.860016,15.240021,15.230011,13.990021,15.179993,15.01001,15.26001,15.290009,13.990021,15.420013,19,19,19,21,21,19,19,21,19,19,19,19,21,19,94.33795,96.40796,93.941956,100.0,1.79,2.2000122,0.0,07/16/2022 06:52:52 PM
The 15. numbers are cell voltages, the 13. are bad cells voltages, the 19s and 21s at the end are internal resistances, the 21s being the bad cells.