The Dropdown component as spec’d in Figma includes a similar pattern of including an optional search input to filter its options.
Not accounted for within the implementation of Dropdown shipped to consumers.
Given several known use cases for a similar pattern (i.e., both in SelectMenu and Dropdown), it might be worth adding built-in support for this use case?
Next steps:
Reach back out to issue author to verify the use case of using SelectMenu on its own without integrating with Dropdown.
If so, then maybe adding the filtering just to SelectMenu would be reasonable.
Auto-centering of the items, and how that relates to having the optional input field.