Also, I have a question for other people with a youtube channel: Should I delete older videos I'm no longer happy with, or just keep them up?
Generally, I would be more inclined to keep than delete. I'm only happy with a couple of videos on my music production channel, but every video increases the chance that someone might discover the channel so it's worth it to keep the videos up even if I could do way better with my current skillset. I have deleted a couple of videos that were so bad and/or different from what I do right now that I absolutely didn't want them to be someone's first introduction to my channel, and there was one video that I unlisted after making a better version of it.
If it's a very old video and it only has very few views and stuff, I would be more inclined to delete than keep.