Get created term entity after creating term programatically
Term::create() returns the entity that the save() method gets called on. So what you want to do is save that entity to a var before calling the save() method on it.

$term = Term::create([
  'name' =&gt; $member[$roster_key],
  'vid' =&gt; 'topic_area',
]);
$term-&gt;save();

//Retrieve the tid of the new term
$term-&gt;tid-&gt;getValue();