What does it mean by (IP - connectionless) but still relies on TCP/IP (TCP - connection-oriented)? If 3-way handshake is handled in Layer 4, why do people mention IP as connectionless since it's not supposed to handle SYN/SYNACK/ACK?

Hi,

I'm new to networking and I'm not sure if I am on the right sub. I'm trying to understand Networking Fundamentals. I'm a programmer but I want to dive into CCNA to improve my knowledge. I bought a tutorial from Udemy and it's mentioned that IP (Internet Protocol), as a Layer 3, can rely on TCP or UDP for transmission (Layer 4).

If Layer 4 protocols are used for ensuring quality of delivery (via 3-way handshake, by TCP), then why is there a need to mention that IP is connectionless? For now, what I know is that connection-oriented data transmission is handled by TCP in Layer 4.

Do some of Layer 3 protocols handle quality of delivery? (Such as packet loss, etc)