These are known ideas, yes. But to know how to do this in the engine, if you were picking it up quickly, would take in the region of 3 to 6 months.
That’s probably why you’re struggling. It’s not just you, it’s everybody new. Some people, with brains like planets, do get a lot done very quickly, but if you see what they’re doing, they still miss the point in a lot of areas, and no doubt have to re-code. In fact many probably give up, but we never hear about that.
If someone did explain it to you, in one go, your head would explode ( no kidding ). Even if they told you exactly what to do, it would take weeks to put the code in.
It would be better to focus on one area, and work on that until you get something working. Point system is the easiest thing you have there. Followed by destructible meshes.
Character and weapon customization ( at the level you want ), is more difficult.
Spawning - it’s just one word. But what you actually need to know about there is character animation, AI, spawning, destroying, points systems, damage systems etc.
Sorry to ramble on.
If you picked one focused area and posted about that, I think you’d get more responses.
Good luck 