I will also add if all your pages can be navigated to via links within your site then there is no requirement to use a sitemap at all.
The only time it becomes necessary is when you have orphan pages, for example, pages that can be only found via a search on the site. In order for Google to find these pages, they do need a sitemap as google bot is not able to type and find these pages.
If you have external links to these pages then that helps but that requires users to post links on other sites which is something you cannot control.
So if your site structure is good then having a sitemap will not offer you any benefit.