Comment by ekr____

Just on a technical note, TLS 1.3 only uses AEAD ciphers where the nonce is determined by the record numbers, so it actually is in principle possible to decrypt the packets even if they are received out of order by trial decrypting with different record numbers. You don't do this in TLS (as opposed to DTLS) because it runs over TCP and therefore you are guaranteed in-order delivery.

DTLS, by contrast, provides a record number hint (the low order bits of the record number and epoch) to assist in record number reconstruction: https://www.rfc-editor.org/rfc/rfc9147.html#name-reconstruct....