I do not know if he is writing in the right place, will you still develop the project? From what I can see you can even write a private server, you only need to have the right knowledge of how to do it

Definition on this line.

WSASend and WSARecv use the PASCAL calling convention, which is not supported by .NET. This may be why it doesn't work The injectable DLL that does the hooking is written in .NET, meaning there is a difference between the calling convention of the new function and the original function.

It's possible to change the calling convention of a Delegate with UnmanagedFunctionPointerAttribute, but only cdecl, fastcall, stdcall and thiscall seem to be supported.

Of course it is possible that it's due to another reason that this hook doesn't work, and maybe we'll have to switch to a different hooking method altogether.

Each packet in PacketType has wrong hex value.
Every packet is sent in Little Endian bytes. That means that most significant byte is actually on the right, not left.
Due to this every packet has wrong numerical value assigned. For example:
Packet ClientEnterServerReq is actually assigned to value 0x1302 rather than 0x0213. 0x0213 is shown in any raw binary dump of data.

Didn't notice if you meant to have them in Little Endian byte order, but it can cause some problems.