My moto z droid f16.mot.xt1650.0 shuts off erratically at 70% power.

My Moto Z Droid F16.mot.xt1650.0 shuts down erratically anywhere from 75% to 50% power. When I go to turn on I get a circle with yellow triangle and exclamation mark. I have run battery check apps that say battery is fine. I have done safe mode, cleared cache, soft reset, factory reset. And everything else I could find online. Even happens when using the moto mod battery pack which makes me question if it is the battery. Seems like this started happening ever since the Oreo 8.0.0 update in Sept’18. If battery replacement is required, can anyone refer to a reliable source. I can do myself. Thanks for any help.