You said "GUYS" like 5 times in the first like 10 seconds of the video and I was laughing because it felt silly, but I think that might be a good thing? Not sure haha.
Anyway, yes your thumbnails need work: Don't be afraid to make the game's logo small as long as you don't squish it or crop it off like you did here. I honestly think your best thumbnail is your WHY SO MUCH HATE one because it keeps the focus on only two things: the text and the FPS angle gun. If you DO want to keep the game logo in (which i think you should, it tends to attract more viewers), don't be afraid to move it and the text over to the side!
As for your video: I think the audio is great, your song choices are good (though I wonder if some of them might be copyrighted) and your speaking volume and pace is great. The video quality isn't as clean as I feel it could be, but I'm not sure what you're using to record or how. Also your logo on the top right feels just a tiny bit distracting. It might help if you take out the background and just make it the logo with transparent background.
As for gameplay itself, I think you were fine but I can't really say, haha; COD games aren't my thing so I'm not your audience! Hopefully someone else can come in to tell you about that.
