How long is too long or short?

Hello everyone,

How many minutes make up a good long form video? Most people I have saw recommend 1-2 long form videos and 5-7 shorts a week. Are shorts 25-45 seconds? Many people talk about these terms without defining what they actually are. I am currently trying to figure out how to start making videos and what niche to make content for. I have many passions, where I want to create content about all of them. Many people I read say start one channel. Others say make a different channel for each different genre of content. Any advice would be greatly appreciated.