That really depends. There are two primary explanations to this phenomenon, which point to opposite answers.
First, a compiler optimization known as "inlining" inserts the body of the called function into the calling function, thereby eliminating the call instruction, but making the calling function bigger.
Secondly, games are usually written in C++...
In IDA, you can find sequences of bytes via Search->Sequence of bytes. That said, if your byte pattern is poorly-chosen (for reasons such as that it includes relocatable byte sequences, or it was created for a different version of the software), the result of the search may well be that the pattern cannot be found in the target binary.
The generated machine code is going to vary by compiler, and even within the same compiler depending on compiler optimization settings. Sometimes optimizations will "inline" functions, removing what was a function call in the code. Sometimes external libraries will be compiled "statically" i.e. their functions get incorporated directly ...
[RAX=0x33307EE0 + RCX=0x0 * 0x8] == [0x33307EE0+0x0] = 0x33307EE0
compare whatever is at Address 0x33307EE0 with r9 register
[RAX=0x33307EE0 + RCX=0x377F1FD0 * 0x8] == [ 0x33307EE0 + 0x1bbf8fe80] = 0x1ef297d60
mov into rcx whatever is there at 0x1ef297d60
you really need to find some reading/viewing material on assembly
it is always better to read a book on ...
By finding the constructor for the structure type that you're looking at, making note of the VTable address, and adding the indicated offsets to obtain the concrete function pointers for the calls in question.
UnityPlayer.dll is the engine itself - it doesn't contain any user-made scripts. Assembly-CSharp.dll is the main user script dll, and if, as you say, it isn't being affected, you're either modifying an unused class, or they moved to il2cpp (in which case there will be a GameAssembly.dll next to the exe) and just forgot to remove the old files.
As you said, the Lua engine is embedded directly into the game. It's inside plugins/GameManagerVC.dll (or GameManagerVC64.dll in case of 64-bit).
So, first step will be finding out, which version of Lua it is. So put this DLL into Ghidra or IDA Pro. The most easiest way of figuring out, what version of Lua it uses, is by searching for "Lua" string ...