Yes, but that’s only part of the flow. TCP/UDP are the base transport protocols, and NSS offload goes beyond that by accelerating other layers of the data-path: NAT, firewall filtering, connection tracking, QoS, PPPoE, bridging, wireless forwarding, etc.
About that PR though, kTLS isn't compatible with NSS, and will actually impact performance. It will end up using software crypto and add extra latency on socket reads (decryption only starts when a read syscall is made) and additional I/O load on the system.
I experimented with it a few years ago (NGINX + ktls option in OpenSSL) and it was causing all sorts of SSL validation and connection issues.