This new search UI is not functional on mobile.
Once you select the search field it goes behind the site logo so you cannot filter by category or relevance/new. If you try, you hit the logo and get redirected to the store.
The new search is essentially useless in my case on mobile.
Edit:
Pressing enter twice after a search term brings you to the original search page so you can still get to the original search interface, with an extra step.