I think it is in part niche dependant. Some niches it's normal to upload once every six months and others you routinely see people go 2x per day. The channels I pay attention to in my niche all upload 5-18 times per week. I mean lots of factors influence the point where the audience feels saturated, depends how good the content is, how fresh the ideas are, how much demand there is for your content at that time, how long your videos are, is it too similar to your last video... If I do multi upload days I try to space out by at least 4-6 hours if they are subscriber directed videos so they have time to watch.
Obviously you can't upload more than you have time to, so just do what fits in if time is an issue.
In certain niches there are reasons why you might want to do a large amount of videos in a short amount of time. Sometimes a hot topic like a new video game or something that's trending will only be trending or relevant for a certain amount of time and you might want to make as many videos on it as possible while people are still interested in it if it's doing really well. My experience with mobile games is that some can "blow up" for a brief window of time and you want to make sure you get your key videos in during that time because 3 months later you may not be pulling the same kinds of views on the same videos. That's niche specific to me, you just have to understand your audience and how the content they like works.
However, >There's no magic number you have to upload to start growing.