Reddit typically isn't the best way to advertise gaming videos. The communities are too big - you won't have a single redditor who cares about your uploads in particular. Building "trust" within a subreddit with participating in discussions means nothing - nobody will remember you, because they're probably clicking on hundreds of links an hour.
For newer Youtubers, it's even worse. Redditors will purposely dislike all your videos if you post something they don't like, because 75% of the time, they're just plain mean. I have never seen such a negative community of people. That doesn't mean there aren't nice people on reddit, it's just that people who sort by "new" on a subreddit typically are very judgemental (or, they're downvoting your post to look their post look better. Happens all the time).
I consider myself EXTREMELY lucky. I can attribute a large part of my success to reddit. (Not that I'm a big youtuber, but reddit brings in those views). I found a community that had 100,000+ subscribers but very few posts a day (it's a very niche genre of videos with very few content creators). I got lucky. For a genre so crowded, like gaming, I'm sorry, but reddit just won't work.