You added both this...
@Html.Raw(Html.CreatePlatformNavigationMenu())
...and this?
@Html.Raw(Html.ApplyPlatformNavigation())
What's your menu provider configuration look like? If you have multiple pages associated with your admin page area you need to have the menu provider registered with all of them, I believe.
And are you dealing with Parent pages that click off to sub-pages? If you have child pages it could be a matter of making sure the menu provider is registered properly for the child pages too.
The MenuProvider works based on the path that is registered to the page, and it the paths that it "knows about" don't match the current page you are on then I don't believe it will render the menu for that page.
I referenced the following and created admin pages and menu items. But for some reason the top CMS menu shows in few pages and not in some pages.
https://world.optimizely.com/blogs/ryan-bare/dates/2019/7/new-cms-ui-navigation/
https://docs.developers.optimizely.com/content-cloud/v11.0.0-content-cloud/docs/adding-and-configuring-menu-items
Missing Page:
Working Page:
Missing these <div>
CMS Version : 11.20.14