Like I said man, never think that the opinion of a few members is the law of how things work here. I would have no problem accepting this submission of yours, because I understand that coming from a place like Speedrun, the requirements here may seem a little boring and unnecesary, the exact same thing happened to me, and I'm always lenient with first time submitters.
And I repeat, I'm ok with the use of cheat codes to unlock cars, tracks, etc, I have done it myself in several games and a couple of purists may disagree but in general it's not a big deal and the submissions tend to be accepted.
Yep, that is exactly what I used to do and I got very frustrated when I was told to leave all the fail attempts in the video because I thought I was being practical by just showing the claimed score, but trust me, you get used to it faster that you would mind. And I understand uploading a video like that to a youtube channel is really not ideal, I would never do that either, but you dont have to. Upload the raw video here and cut it for your YT channel.
Well, I hope you give it a second try and submit a few scores here as well. Wish you the best :)