Hi! Thanks to both of you for your answers.
I managed to get it working by using a different approach-via Wi-Fi. However, I’m still curious: why couldn't I connect via UART?
I suspect it might be related to the camera's firmware. It seems like the Unit CamS3 5MP Wi-Fi doesn't have default firmware to stream JPEG over UART. Is that correct? I’d love to understand why it works over Wi-Fi but fails over UART. I either managed to connect with camera (pin 17 and 18) but couldn't get any data back.
Any insights would be greatly appreciated!