The Popover component accepts custom elements as children. This means that you can show your component as dropodown when the trigger is activated. Said that, if you're using custom elements you have to follow all the ARIA requirements and introduce the required behaviours, like focus handling (eg. using the autofocus attribute) and keyboard navigation with the roving tabindex. There is also a react package to easily handle this.
Move focus on the trigger if closed. If opened move the focus inside the popover. If no focusable elements are found, move focus outside and close the popover.
Open the menu and set the focus on the first focusable element inside the popover.