But shadowsocks is a VPN. What makes it better than other offerings?
See https://shadowsocks.org/ for info.
On your local workstation, it exposes itself as a SOCKS5 proxy. But to communicate with the shadowsocks server, it uses a proprietary protocol which is not SOCKS5 and does have a key exchange process. Either way, these details don't affect its ability to be detected.
> VPN is not made to be undetected
"VPN" is not just one technology. Many vendors of VPN software do claim that their software is made to be undetectable. One example is shadowsocks, but there are other vendors who also claim that.