How can I control the width of a td tag?

I simplified your html to this

<div id="divMain">
  <table>
    <tr> <td>BAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA</td>
      <td>blah</td>
    </tr>
  </table>
</div>

HTML:

and your css to this

#divMain {
  width: 75vw;
  max-width: 75vw;
  border: 1px solid red;
  padding: .5vw;
}
table {
  display: block;
  width: 98%;
  max-width: 98%;
  border: 2px solid green;
}

td {
  width: 50%;
  max-width: 50%;
  overflow: hidden;
  line-break: anywhere;
  overflow-wrap: break-word;
  word-wrap: break-word;
  hyphens: auto;
  border: 1px dashed pink;
  padding: .5vw;
}

Code (CSS):

and it all looks great

You will be able to take out the second column and expand the width if that's what you need.