example of what an extremely barebones among us hook looks like (no graphics)

main.cpp

// use il2cppinspector to create a c++ scaffolding project
// import minhook
// replace user/main.cpp with this
// play around! this basically shows you how to hook any function you'd like
// it's obviously not at all what you'd call "complete", but it contains enough stuff i had to figure out through trial and error
#include "pch-il2cpp.h"

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include <iostream>
#include "il2cpp-appdata.h"
#include "helpers.h"
#include "MinHook.h"
using namespace app;
#include <string>
#include <locale>
#include <codecvt>

// this is stuff for setting up the addchat hook. paste from the il2cpp functions definitions
typedef void addchat(ChatController * __this, PlayerControl * sourcePlayer, String * chatText, MethodInfo * method);
addchat* orig_addchat = nullptr;

std::string utf16_to_utf8(std::u16string utf16_string) 
{
	std::wstring_convert<std::codecvt_utf8_utf16<int16_t>, int16_t> convert;
	auto p = reinterpret_cast<const int16_t *>(utf16_string.data());
	return convert.to_bytes(p, p + utf16_string.size());
}
// pasted from https://github.com/ExtraConcentratedJuice/ChristWareAmongUs, StringUtility.cpp
// you don't need to change this.
std::string stringify(String* netString)
{
	if (netString == NULL)
		return NULL;

	uint16_t* buffer = new uint16_t[netString->fields.m_stringLength + 1];
	memcpy(buffer, &netString->fields.m_firstChar, netString->fields.m_stringLength * sizeof(uint16_t));
	buffer[netString->fields.m_stringLength] = L'\0';
	std::string newString = utf16_to_utf8((const char16_t*)buffer);

	delete[] buffer;

	return newString;
}

// an example hooked plugin
void hook_addchat(ChatController * __this, PlayerControl * sourcePlayer, String * chatText, MethodInfo * method) {
	GameData_PlayerInfo* player = PlayerControl_get_Data(sourcePlayer, NULL); 
	// stringify()ing the text is important, you're starting out with this nebulous String object that if you try to put into cout will just return a pointer
	std::cout << stringify(player->fields.PlayerName) << (player->fields.IsDead ? " (DEAD)" : "") << ": " << stringify(chatText) << '\n';
	return orig_addchat(__this, sourcePlayer, chatText, method); // make sure to return flow back to the normal function! ...if you want
}
// Custom injected code entry point
void Run()
{
	NewConsole(); // create a console
	// start setup bullshit 
	auto domain = il2cpp_domain_get(); printf("[0] Domain gotten.\n");
	il2cpp_thread_attach(domain); // i'm not sure if this is necessary
	auto assembly = il2cpp_domain_assembly_open(domain, "Assembly-CSharp"); printf("[0] Assembly gotten.\n");
	auto image = il2cpp_assembly_get_image(assembly); printf("[0] Image gotten.\n");
	// end setup bullshit
	// start what should be in a function if you ever expand upon this
	auto chatcontroller = il2cpp_class_from_name(image, "", "ChatController"); printf("[0] Class gotten.\n"); // get the class you want 
	auto addchat = il2cpp_class_get_method_from_name(chatcontroller, "AddChat", 2); printf("[0] AddChat: %x\n",&addchat); // get method from name (2 is the number of arguments, this is important)
	printf("[0] If this is not AddChat, there's a bug in the code: %s\n", il2cpp_method_get_name(addchat)); // ensure that you grabbed the right function
	uintptr_t pointer = (uintptr_t)addchat->methodPointer; printf("[0] Pointer gotten\n"); // get the pointer to the function!
	// Initialize MinHook.
	if (MH_Initialize() != MH_OK)
	{
		printf("[0] minhook is not ok!\n");
	}

	printf("[0] CreateHook return code: %x\n",MH_CreateHook((void*)pointer, &hook_addchat,
		reinterpret_cast<LPVOID*>(&orig_addchat))); // hook the pointer you just got

	printf("[0] EnableHook return code: %x\n", MH_EnableHook((void*)pointer)); // enable the hook

	printf("[0] Chat logger loaded. Have a very safe day.\n__________________\n\n"); // :thumbsup:

}