When editing in a table I have the following (in wiki markup)

||Heading||Heading||
|Item | * list item 1
* list item 2
* list item 3 |

which renders like

If I then go to list item 1, delete the text "list item 1" and then backspace to remove the bullet, I am left with a hard line break above the bulleted list that I cannot remove at all in the new editor.

source code from source editor:

<table>
  <tbody>
    <tr>
      <th>
        <p>Heading</p>
      </th>
      <th>
        <p>Heading</p>
      </th>
    </tr>
    <tr>
      <td>
        <p>Item</p>
      </td>
      <td>
        <br/>
        
        <ul>
          <li>list item 2</li>
          <li>list item 3</li>
        </ul>
      </td>
    </tr>
  </tbody>
</table>

To remove the hard < br > character I have to use the source editor.

You need to either not put in a hard < br > or make it so that backspace / delete can remove it.