The "OnValueChanged" event for TextMeshPro InputField is triggered before the new value is fully processed.

The suggested workaround is to employ a one-frame-delay coroutine for operations that require the updated text:

public void CheckNameLength()
{
StartCoroutine(DelayedCheckNameLength());
}

private IEnumerator DelayedCheckNameLength()
{
yield return null; // wait for one frame

Debug.Log($"Name : {nameInputText.text} : length {nameInputText.text.Length}");
}

As for the length of the text, this is also expected as the TMP InputField appends the ZWS unicode to handle the cursor on new lines.