Website’s navbar on top vs navbar fixed at bottom for mobile size?

For mobile size I usually add burger menu icon on top of the page (or menu links if just couple) with option to open and display all menu links in overlay, but more and more I see approach where the navbar is added to bottom as fixed, where thumb reaches it better. What type of menu would be better to use? People are used to menus on top, but I think this is starting to change.