Do you edit it post recording? I don't think it's grainy, though I see the problem with the chat and I see what you mean by bright, but overall I think it's okay. I wouldn't say horrendous but I see where you are coming from. I'm quite harsh with myself too.
I think you mentioned that game was the first time you played it so what you could do is edit it post recording and sharpen the image so that the chat and other various text comes out more clear. Alternatively you can always increase it to 1080p, which I highly suggest. If not, you can always edit it to look better.
This was your in 720p:
View attachment 17395
These are two shots of my videos that I chose since it had some small text on the screen and it is in 720p:
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View attachment 17397
I edit my recordings to compensate for some quality degradation and just make the image appear more crisp and smooth. You can see that the text in the corners are about the same size as yours but appear more clear.