Currently, the only way to close a given tab is to have the tab open, and hit the note ellipsis menu before tapping “Close Note”. The “Close Note” button being where it is is perfectly fine, but it’s cumbersome to get to when one could just close tabs in the tab menu as well.
Oddly the checkmark showing the active tab isn’t even located all the way to the right in the tab menu, as though there were room already alotted for a close button…
This might be a theme thing, or due to the size of your screen. On mine (iPhone 13, default theme) the checkmark has the same space to the right of it that there is to the left of the file icon.