Menu Options vs Collections

[Barchefs]

As we dive into designing our site. I had previously asked about Categories and how they are different from collections. Somewhere in the shopify directions it did tell me that categories were different. I have numerous questions. I kind of understand but I don't get the logic.

1. When shopify said categories are different did they mean the categories or the "menu" items as the same thing? 

2. Is it correct thinking that Collections will typically mimic your menu/categories? Not always but I'd think somewhat the same is that right?

3. I imagine has to do something with the liquid format for programming etc...?

4. Can someone tell me the importance of the (Menu/Navigation) name vs the Collection Name when it comes to SEO optimization. (ie... currenlty our collections are using chatGPT to help us optimize SEO and are longer and klunkier a little. My current menu names are short and concise so it looks good on the site. For example menu header says LED Games but our collection name is LED Light-Up Games for events etc... etc... Is this correct logic as I am assuming the menu name that shows under (Menu/navigations) is not too SEO Important?

5. When I do my menu can I just have that original menu link directly to collections and avoid submenu entries or I need to make submenu entry for each thing and link that to each collection. 

Sorry for all these questions it's just not clicking right now and the directions leave room for improvement lol.