What model did you buy/return?
I'm using multiple Tapo cameras and although I had to set up an account initially for configuration, that account is only used when I want to actually change camera configuration. Unless I need to do that the cameras are completely blocked from the Internet.
They work fairly well with RSTP on Frigate & Home Assistant although they do lock up once in a while, but they were only $15. If I remember correctly not all TP-Link's cameras support RSTP and the company is terrible at documentation, so making sure you buy a camera that supports the protocol isn't all that easy.
I also have Foscam and Dahua cameras and they have been bulletproof.