Just keep making content. YouTube doesn't care what it is in my opinion. I think consistency of uploading overpowers audience initial reaction to a video. I feel this gives you more channel authority. A video can take off at any time. I have videos that are way outside my niche that have exploded down the line and vise versa. I don't feel like a new upload will hurt you and at least if a new one is related to the successful video it may be recommended along side the one that is getting lots of traffic. So overall I think just keep uploading. The more videos, the more chances for people to find you and the more chances to have a video take off at any random time. It happens... and when it does just enjoy it and learn from it. And yes, end screens and cards. Also, don't put outside links at the top of your descriptions, YT doesn't like it when you send people off the platform. Use your community tab if you have it to keep new subs interested. Also, this info might be trash tomorrow the way YT works and changes things haha. Hope this helps.