You can't edit maps because those are cooked assets. You could only do it if dev released them as unreal project, which is unlikely. But we might get example unreal project with placeholders such as spawn points, game mode, etc, so we could make our own from scratch.

Google or something similar would be your friend here; TKA is made in Unreal Engine 4.27 so it is remarkably easy to simply extract the assets you're looking for instead of ripping them. That said, please only do so for modding. Anything else opens you up to either civil or criminal consequences depending on your country, and stealing from small creators like this is just extra messed up.

That said there are already several examples of map mods done that you could download and extract to get an example of their file structure. I'd recommend downloading UE 4.27 via the Epic Games Launcher and use something like FModel to open and extract the pak file. Technically Unreal comes with a built-in tool for packing and unpacking those files, but unless you're comfy with the command line I wouldn't recommend it.

I want to point out to anyone that may be worried with the information I have given here that the main pak file is still secure because it's encrypted. With SHA-256 no less. If ya'll can truly break that, I'm sure the Pentagon would love to have a word with you. lol