I'm writing mine from scratch in C#, I just looked through
XiuzSource, the packets seem to be the same and it doesn't seem like the VACFlag packet is being handled there, same as the other repacks I've looked at.
I just timed my handler for ViewAllCharacters and it sends out everything the client needs in 0.5s, and in-game the UI itself loads after roughly 10s.
EDIT: the release date is 2010, I didn't even check it.. do u have a more recent link for me? I can't find a later version. (I found a repack called Vintage from 2016 but it's the same case there)
EDIT 2: seems like the loading for 10s issue was because I didn't send a NoCharacters (4) packet after sending the world characters. I just found that out by playing around with the packets a bit more lmao. (their timeout for server response on that is roughly 10s, interesting)
EDIT 3: apparently in the count packet, the first integer is the amount of worlds and the second is just the amount of characters in general, the timeout happened because I had a different value there (same as odinms, more than 1) and it kept on waiting for more world characters to be sent from the server.