TLS 1.3 is much better than TLS 1.2, and has fewer options and knobs (e.g. no need to choose cipher suites), but it is not what a modern protocol designed from scratch would look like. For that you should look at WireGuard, or the general Noise Protocol Framework.

For custom protocols, libsodium would be a popular modern approach. If you need compatibility with TLS, try locking down TLS to only version 1.3, or if you can't do that, lock it down to only TLS 1.2 with tls_ecdhe_rsa_with_aes_128_gcm_sha256.