Battery won’t charge, only code p0420 for catalytic converter?

I have a 2005 Prius with 217,000 miles on it, had the battery refurbished about a year and a half ago and it’s been running well since. Though apparently it’s burning oil since it was low when I went in for my last oil change and had started driving rougher right before then.

Now, it’s driving really strangely. Randomly brakes while driving, accelerating slowly, goes betwee hovering at 1-2 bars of battery to charging rapidly, and the engine will keep charging even after full.

Worried I did some damage driving on low oil, I went to pep boys to get the code and the only one it shows is P0420 - catalytic system efficiency below threshold.

as far as my knowledge goes, the catalytic converter shouldn’t be causing battery issues. But I’m confused by the lack of any code relating to the battery! Does anybody have any ideas to work with until I can get an appointment with a mechanic?