Use links for destinations
A navigation item that changes the page should be an anchor with a real destination. Buttons are for actions such as opening a menu or submitting a form.
Keep the navigation label clear and give the navigation landmark a name when a page has more than one navigation region.
Keep focus visible and logical
Tab through the page without a mouse. Each interactive item should receive a visible focus style, and the focus order should follow the visual reading order.
If a mobile menu opens as a panel, make its open and close controls obvious. Close it when a destination is selected and return focus to the menu button if the panel closes without navigation.
Check the small-screen version
Verify that labels do not wrap into confusing shapes and that touch targets have enough space. Test zoom and keyboard use, not only a quick tap on a phone.
A working keyboard flow improves the interface for people using assistive technology and for anyone navigating without a pointer.