What actually paints the blue Send/Go key on iOS? Blur is rarely enough. Compare element kind, whether the hint is set before focus, and remount.
Content rule: Enter → newline unless caret at end + trailing newline → submit (logged). Dynamic mode only changes the attribute; iOS may still paint Return on textareas.
Tap each once cold. This is the fairest test of whether iOS honors send at all.
1) Matrix input send is blue, but textarea send stays Return → element kind, not blur.
2) Static send on input works; dynamic never → traits frozen for that focus session / node.
3) Remount-on-change helps only if keyboard fully dismisses and you refocus the new node.
4) Blur without keyboard dismiss + same node → nothing changes (your observation).