Replaced battery, now phone stops responding or reboots

Replaced the battery, did battery calibration.

When fully charged and plugged in, phone seems fine.

When unplugged and with battery around 90, camera app consistently crashes. Down around 70% I can't even unlock the phone, the touch response becomes so laggy.

Unplugged and reseated everything. I got the aftermarket battery from ifixit, has anyone else had any issues? Wondering if it just can't supply the power needed.