Until you try those batteries in a new phone, you probably won’t know why they aren’t working. The two most reasonable explanations for your phone issues are, (1) phone is malfunctioning or (2) both batteries are going bad, including the new one.
I’ve had spotty luck with $11 replacement batteries for my iPhone. I’m still using my iPhones 6 and 7.
Yeah, lots of knock-offs out there, of questionable origin. I bought one for a Samsung, and though the actual capacity was about 80% of the original, it has held up amazingly well for over 3 years on an old phone I only use at home as a WiFi terminal. It's roll of the dice.