This topic gave me a lot of clue

maybe it will helpful for you too. But remember that packets ID's was changed and now for example packet $2A have other signature. Remember also that SwordCrypt table that are used also to decode kal *.pk files are different for packets and files (you can find this table easy checking high entropy on engine.exe process dump if you have no exp with RE and ASM).
First packet have enc/dec AES ECB key but it's encoded by INIX invention algorithm that if i good remember take 52 bytes as input and output 16 bytes.
AES is also bit strange coz for 128 bit input buffer is made little/big endian change every 4 bytes