Update on my previous post (one above) Got a (fake) battery and installed it, works like a charm so far. I did use an OEM charger before though, which might've caused the defect. Switched over to an official charger just to be sure. Did anyone else here use a fake charger, might be the cause of this?

Same here Model: MBP 2015 13" What: battery died after installing Big Sir, service recommended. Unplugging shuts off computer. Returning to older OS doesn't fix it. Did anyone try replacing the battery and keeping it on Catalina? I don't want to waste money on a battery if the problem might lie in the circuitry or if it will just die again. Already tried SMC and PRAM and all the other standard fixes of course.